Abstract: A power semiconductor device (2) has a first main electrode (S) for coupling to a first supply line (3), a second main electrode (D) coupled to a first terminal (4) for connection via a load (L) to a second voltage supply line (5) and an insulated gate electrode (G) coupled to a control terminal (GT) for supplying a gate control signal to enable conduction of the power semiconductor device (2). An open-circuit detection arrangement is integrated with the power semiconductor device (2) for providing an indication that a load (L) coupled to the power semiconductor device (2) is open-circuited. The detection arrangement has a reference current (Ir) providing arrangement (7, R3, R4, R7, Q1, Q2) and a current deriving arrangement (Q3, Q4) for deriving a current (Id) dependent on the voltage at the second main electrode (D).

Abstract: A circuit for diagnosing the state of a load connected to a driver includes a DMOS transistor interposed between a terminal of the load and voltage comparator circuits. The DMOS transistor limits the maximum voltage input to the comparators to thereby reduce the circuit area occupied by the comparators and consequently to reduce the cost of the diagnosis circuit.

Abstract: A current flowing through the automotive battery and the battery voltage are measured by the battery current measuring means and the battery voltage measuring means. The battery is connected to a plurality of wiring harnesses which in turn connect to a plurality of loads. Data on normal resistance values between the battery and the wiring harnesses as produced by each of the loads being activated are stored and held in the load current data holding means. When the resistance value comparison means determines that the resistance value between the battery and the wiring harnesses calculated by the resistance value calculating means does not agree with the data of normal resistance values between the battery and the wiring harnesses held by the load resistance data holding means and produced by each of the loads being activated, it is decided that abnormal currents are flowing through the wiring harnesses.

Abstract: An intravehicular auto harness tester consisting of a first housing unit mountable within or upon the dashboard of a motor vehicle containing three small light emitting diodes with wiring one wire per diode leading thereto and then therefrom and ultimately as one wire to ground, coupled with one resistor per diode, with such wiring entering the housing unit and leaving it by way of a coaxial cable leading to a second housing unit located typically in the trunk of the vehicle with the wiring within the coaxial cable being connected within the second housing unit to each of three prongs one wire per prong and with one wire to ground via a female socket pocket all located at a front end of the second housing unit for purposes of interfacing with an intravehicular auto harness power plug.

Abstract: A diagnostic test apparatus for simulating pin open circuit, pin short to ground and pin shorted-to-voltage fault conditions at each pin of each connector of an engine controller module (ECM). The apparatus includes a parallel port coupled to a demultiplexer circuit. The outputs of the demultiplexer circuit drive a plurality of relay drivers, which each, in turn, control independently a single relay coupled between one particular pin of an ECM connector and its associated circuit line on the vehicle wiring harness, when the apparatus is coupled in line between the ECM connector and the vehicle wiring harness. The apparatus may be controlled by an external computer such that the three above-mentioned fault conditions may be initiated automatically.

Abstract: A fail check device and method for switching signal lines, wherein PWM signals are sent out onto PWM signal lines through a PWM signal output/survey circuit. Based on the level of the PWM signals to be sent out and the level of the PWM signals actually sent out, a PWM mismatch signal (logical) is produced. The produced PWM mismatch signal (logical) has a value which indicates a fault when the PWM signal lines are in a state of breakage or short circuit to a ground or the PWM signal lines in a predrive circuit are short-circuited to the positive wiring of a power source. Therefore, by using the PWM mismatch signal (logical), a breakage in the PWM signal lines or a fault in the predrive circuit can be detected by a control CPU.

Abstract: An equipment and method for detecting electrical leakage in an electric vehicle. For detecting occurrence of leakage in an alternating-current motor for driving the vehicle, a source-side transistor of an inverter is turned ON and a sink-side transistor is turned OFF. When leakage occurs in the motor, there arises an electrical path to an electric leakage detector through the grounded portion from the transistor on the source-side, the motor winding, and the leakage portion. Due to a current flowing in the electrical path, the electrical leakage detector determines that the leakage is present, and the result is notified to the ECU (electronic control unit). On the contrary, the source-side and sink-side may preferably be turned OFF and ON respectively. It is unnecessary to turn ON all the source-side or all the sink-side transistors. The leakage in the motor can be detected without misinterpreting noise on the battery-side as viewed from the inverter.

Abstract: An automotive electronic circuit analyzer that plugs into an automobile's electronic control module is disclosed. The disclosed analyzer includes positive and negative load sensing cells each having a series resistor coupled to an ECM load via the ECM connector and having an LED transistor for conducting current when the ratio between the load and the series resistor exceeds a predetermined value. A regulated power circuit for sinking current from the positive load sensing cells and for supplying current to the negative load sensing cells includes a timing circuit for controlling the active power pulse width so that the LEDs are illuminated with high frequency, short duration power pulses to indicate a shorted load.

Abstract: A portable diagnostic device for checking electrical signalling systems of road going trailers. The device has several receptacles for connection to a corresponding receptacle or pin connector of most types of trailers. An electrical circuit includes switches for energizing individual signalling or illumination circuits of the trailer individually, and indicating lamps for annunciating circuit operability. The device, which is contained on a wheeled cart, has its own power supply and circuit overcurrent protective devices, and is thus independent of a tractor which normally generates the signals. The device enables a shop to perform a safety check for many varieties of trailers, while remaining independent of the tractor vehicles associated with the trailers.

Abstract: A method of determining a measurement value (U.sub.-- M) utilizes a calibrating operation and a measuring operation together with an operational amplifier (OP) having an output voltage (U.sub.-- A). The measurement value (U.sub.-- M) represents a current (I) flowing through a load (L) in a motor vehicle having a battery. The battery has a terminal of high potential and a terminal of low potential with the difference between the potentials being the battery voltage (U.sub.-- BATT). The load (L) is connected into a load current circuit and a measuring resistor (R.sub.-- M) also is connected into the load current circuit conducting a load current (I) which, in turn, causes a voltage (R.sub.-- M.cndot.I) to drop across the measuring resistor (R.sub.-- M). The method includes the steps of: amplifying the voltage R.sub.-- M.cndot.I across the measuring resistor (R.sub.

Abstract: An apparatus for diagnosing the presence and location of faults within a vehicle's electrical system includes a signal generator for generating an a.c. test signal; a switching circuit connected to an interface between the system's ECU and the system's components for selectively and sequentially applying the a.c. test signal into each electrical lead therein; and a first detector connected to the system's common ground for detecting the system's response to the applied signals, thereby obtaining a set of transitory characteristics for the vehicle's electrical system.

Abstract: A short circuit detector circuit (10) for detecting when a sensor (2), such as a tachometer sensor in automotive applications, is operating normally and when the sensor is short circuited is disclosed. The detector circuit (10) comprises a reference signal input (16) for receiving a reference signal, and a closed loop (22, 24, 12, 14, 26, 34, 32) having a predetermined loop gain (K). The closed loop has a first input coupled to the reference signal input, a first output (12) coupled to drive the sensor with a signal dependent on the input signal and the predetermined loop gain, a second input (14) for receiving a feed back signal from the sensor and a second output (36) coupled to the first input for providing an output response signal dependent on the operation of the sensor. The value of the predetermined loop gain is selected so that the output response signal is an undamped oscillation for normal sensor operation. The detector circuit (10) further comprises means (4, 50, 52, 54, 56,.

Abstract: A diagnostic testing apparatus for testing an automotive IAC motor normally controlled by pulse signals from the electronic control module (ECM) of an automotive electrical system, which apparatus is coupled between the ECM and the IAC motor circuits and provides first circuits re-establishing a normal signalling communication therebetween, and second circuits comprising parallel test circuits including indicators and switches constructed and arranged for indicating faults in the component.

Abstract: Loads, such as power relays controlling wipers, windows and lights are connected to an automobile battery through individual transistor drives that are controlled by a microcontroller. A switch, connected to the microcontroller, is operated to activate each drive. The microcontroller checks the load characteristic when each drive is activated and inactivated. When the load is inactivated, it is part of a resistance network producing a test voltage that is digitally converted and supplied to the microcontroller, which compares the test voltage to a stored voltage to determine if the load is correct. An analog multiplexer is controlled by the microcontroller to select the voltage produced for each load.

Abstract: A device for testing a multi-terminal electrical service receptacle on a towing vehicle includes an electrically insulative body of elongated shape having forward and rearward faces. Electrical contacts are disposed in the forward face to engage the terminals of the receptacle. Light-emitting devices such as bulbs are disposed in the rearward face, and are connected by way of electrical conductors to the corresponding contacts in the forward surface. During use of the device, the illumination of a particular light signifies the validity of the corresponding electrical circuit involving features of the towing vehicle.

Abstract: A multi-test, hand-held instrument and method for testing manifold absolute pressure (MAP) and mass air flow (MAF) sensors includes a housing enclosing a battery and an electrical circuit. The electrical circuit can test d.c. voltage output signals and frequency output signals from MAP/MAF sensors and can test continuity and battery strength. Electrical leads extend outwardly from the housing and are connectable to the sensor being tested. A pair of light indicators, comprising LEDs and resistors connected in parallel, are selectively illuminated to allow the test instrument to be used to test both MAP and MAF sensors, and to test these components on different makes and models of vehicles.

Abstract: An instrument for performing electrical tests includes a housing adapted to be held in the hand. A conductive probe and a two-conductor power cable adapted to be connected to a vehicle battery protrude from the housing. Red and green light emitting diodes (LED's) mounted in the housing are operatively interconnected with the probe and power cable through circuitry which causes the red LED to glow when the probe contacts a positive voltage, and the green LED to glow when the probe contacts a low voltage, ground, or a negative voltage. Continuity testing may be performed by contacting the probe against one terminal of a device to be tested, and contacting the other terminal of the device to ground or to an auxiliary test lead extending from the housing, causing the green LED to glow. The instrument includes a momentary contact switch that permits the probe to be energized by internal connection to the positive or ground input terminal.

Abstract: A plurality of sensors, such as a door handle lift switch, a headlight switch, and an ignition switch, are normally provided in an automotive electrical system. A master microcontroller normally is coupled to each of these sensors for receiving a signal therefrom and responsive thereto generating a corresponding controller signal. Power drivers, each operatively coupled to the master controller, normally are provided for energizing and powering loads coupled thereto, with each load being either an indicator or actuator that is operated responsive to its corresponding sensor. The self-diagnostic method includes the steps of mechanically actuating a selected one of the sensors, and then electrically actuating a first confirming indicator, such as an audible chime, indicative of the master controller receiving and successfully processing the corresponding sensing signal.

Abstract: An integrated circuit including a comparator having two output states and being responsive to a voltage developed across a shunt in the circuit so that the comparator assumes one of its two output states when the voltage developed across the shunt is greater than a threshold switching voltage and the other of its two output states when the voltage developed across the shunt is less than the threshold switching voltage. The integrated circuit additionally includes a threshold switching voltage sensitivity control circuit, coupled to and controlling the comparator, for controlling a sensitivity of the threshold switching voltage to changes in a supply voltage of the lamp circuit and for controlling a sensitivity of the threshold switching voltage to changes in temperature of the integrated circuit.

Abstract: Method and apparatus for monitoring the operation of a plurality of electrical loads in an automotive vehicle with a single current sensor. The current sensor detects the change in the total output current associated with the electrical loads and generates an output signal based on the current change. The apparatus also includes a controller which activates each electrical load at a given time to obtain a like plurality of timing signals so that each electrical load receives a portion of the output current. The controller processes the output signal and the timing signals to obtain a diagnostic signal related to an operating condition of at least one of the electrical loads. Finally, the controller controls an operating state of the at least one of the electrical loads based on the diagnostic signal.

Abstract: The invention is directed to an arrangement for monitoring an electric consumer in a motor vehicle. The consumer can be actuated by at least one pulse-shaped control signal formed by a control unit with this actuation taking place via a switching device. This arrangement includes a device for detecting electric variables in the region of the consumer and a device for comparing these variables to pregiven limit values as well as a device for recognizing a fault on the basis of this comparison. The device for recognizing faults evaluates the comparison result for recognizing a fault condition pursuant to the actuating state of the electric consumer.

Abstract: An input protection circuit protects a multiplexer used in an automotive breakout box for coupling to an electronic control module (ECM) of an automotive vehicle. The input protection circuit includes resistors connected between the input and the multiplexer and a negative feedback amplifier connected to the output of the multiplexer. The negative feedback amplifier provides a virtual ground. Additionally, the inputs to the multiplexer are clamped to within one diode forward voltage drop of electrical ground by diode pairs.

Abstract: Circuitry for monitoring the function of electric load, an output stage and a control circuit for driving the output stage and the lines that connect these elements. The circuitry includes at least one fault acquisition logic that is connected in parallel with the output stage. The fault acquisition logic has a terminal that connects to an input of the output stage and another terminal that connects to the output of the output stage. The fault acquisition logic also is connected to a reference potential. The fault acquisition logic has a comparator for comparing potentials for determining fault conditions. Detected fault conditions may be stored in a buffer memory that connects to a main memory. The buffer memory may also have a time delay associated with it. The circuitry also may include a coder for encoding signals indicative of the fault conditions that are detected by the fault acquisition logic. The circuitry may further include a safety disconnect to protect the output stage against overload.

Abstract: An auto diagnostic apparatus having jawed, needle-toothed clips for connection to variable output wires of engine sensors adjacent to the sensors, and a processor which converts the output voltages to output values in reader friendly units understandable to the auto technician, and which stores and continuously updates the minimum and maximum output values for diagnosing intermittent or periodically interrupted electrical current. The needle-toothed clips establish an electrical connection to the variable output sensor wire without damaging the insulation or integrity of the sensor wire.

Abstract: A tester for testing sealed lamps and lamp circuits of vehicles includes an elongate housing. The housing has pointed projections extending from one end wall to be received in a base of a lamp and has blunt projections with recesses in the other end wall to receive the prongs of a plug or pigtail which is normally inserted into the base of a lamp. Each of the ends of a bottom wall of the housing have two ports through which light sources, preferably LEDs, are visible and light when the lamp or circuit is functional. A battery is also carried in the housing for the lamp circuit. In a preferred form, the end walls are slidably held by the housing so as to be removable for replacement purposes and to facilitate manufacture.

Abstract: An automotive electrical system including a wiring harness incorporates the dedicated test line passing through critical connectors and components for allowing detection and isolation of improperly connected connectors. The dedicated test line can feed through expansion connectors, termination connectors, and junction blocks. Connector fault detection and isolation is achieved using time-domain reflectometry after final assembly, during vehicle servicing, or on-board during vehicle usage. A large number of expensive and inconvenient vehicle quits and tow-in's are avoided that would otherwise occur.

Abstract: An automotive electrical system including a wiring harness incorporates a dedicated test line passing through critical connectors and components for allowing detection and isolation of improperly connected connectors. The dedicated test line can feed through expansion connectors, termination connectors, and junction blocks. Connector fault detection and isolation can be performed as a test after final assembly and during vehicle servicing. A large number of expensive and inconvenient vehicle quits and tow-in's are avoided that would otherwise occur.

Abstract: An electrical sensing circuit has a sensor device and an indicator such as a warning light. The system of the present invention continuously monitors the operational status of the sensing circuit. Normally open sensors are provided with a resistance across the open circuit contacts to provide a small leakage current. For each sensor, high and low comparators are provided. The high comparator is ground seeking and is used to detect closure of open circuit sensors, grounded connections and systems tests. The low comparator detects open circuits or high resistances such as might be caused by broken or loose wires, improperly connected sensors or electrically degrated sensors. The comparators drive logic components, which in turn drive indicators of circuit operational readiness.

Abstract: A low-frequency power amplifier with an integrated BTL output circuit drives a load. The amplifier incorporates a bias circuit for supplying a bias voltage to each circuit composing the amplifier, a control circuit for switching between the normal operation mode and the mode for detecting the load being in an open-circuit condition, a detector circuit for detecting the load being in an open-circuit mode by supplying current to the load and sensing the current flowing through the load, and an output circuit for telling an external circuit of the integrated circuit that the load is in an open-circuit mode. All these circuits are squeezed into a single chip. The control circuit controls the bias circuit and detector circuit. During normal operation, the BTL output circuit is in an operative state, while the detector circuit is in a nonoperative state.

Abstract: A tester for power operated vehicle antennas is designed to be inserted serially within the power antenna's operating circuit and utilizes light emitting diodes to indicate proper circuit operation. A flexibly positionable fiber optic cable can also be utilized to permit the viewing of illuminated diodes from a remote location.

Abstract: A controller for a device moving along a complementary path to a conveyed object, derives basic speed input from the object conveyor and uses a non-invasive sensor system to detect the proximity of the object. The sensor system controls electronic logic which causes a drive unit to match the speed of the device to that of the object over the complementary path. The controller returns the device to the start of the path for iterative utilization.

Abstract: A portable apparatus for checking the wiring orientation at electrical connectors of trailers or trailer towing vehicles is described. The housing of the apparatus supports a rotary switch and a plurality of multi-terminal connector plugs and/or receptacle portions. The rotary switch has a plurality of switch positions with indicia at each switch position indicative of a particular electrical function such as a particular lighting system in the trailer or trailer towing vehicle. Each switch position of the rotary switch is connected to each terminal positioned on each connector portion at a location that is industrially standardized to electrically couple an electrical system in the trailer towing vehicle to a corresponding electrical system in the trailer. By moving the rotary switch from position to position the orientation of the wiring at the connector on the trailer or trailer towing vehicle is checked by sequentially activating the electrical systems in the trailer or trailer towing vehicle.

Abstract: An automated test system makes voltage and resistance measurements. The breakout cable is connected between the vehicle electronic control module and the vehicle sensors and controls. Resistance measurements are made between a selected pair of connector pins of the breakout cable by connecting a current loop (which includes a power supply and a known resistance) through a first multiplexing circuit to the selected pair of pins. A voltage measuring circuit measures voltage across the known resistance and between the pair of pins. The voltage measuring circuit includes a second multiplexing circuit and a voltmeter. The second multiplexing circuit receives inputs from the various pins, as well as from opposite sides of the known resistance in the current loop. The second multiplexing circuit provides its output to the voltmeter for measurement. By measuring the voltage across the known resistance, and the voltage between the selected pair of pins, the resistance between the two pins can be derived.

Abstract: An apparatus and method for testing electrical loads such as appliances connected with a DC source in a motor vehicle. The loads receive their signals causing them to operate from an electronic control unit. The latter is connected with a diagnostic computer in a manner so as to comply with the industrial standard DIN/ISO 9141. The diagnostic program is stored in the computer, for instance on a diskette. During a test, a precision resistor or shunt is connected in the current path between the DC source and the load. When the load to be tested has been turned on by the diagnostic computer the precision resistor leads to produces a voltage drop dependent on the current flow in the load. Such voltage drop is measured and compared in the diagnostic computer with a rated value specific for the load. If there is a difference the size of the difference provides information indicating the nature of the fault or malfunction of the load.

Abstract: A method of automatically checking components and associated wiring of electrical control associated with a microprocessor controlled transport refrigeration system. The transport refrigeration system has a prime mover which drives a refrigerant compressor and an alternator. The control includes a battery and a current shunt which measures battery current. During the automatic checking procedure, the prime mover is off, to provide a zero alternator output. Upper and lower battery current draw limits are provided for each component to be checked. Each of the components to be checked is energized and de-energized, with the microprocessor individually and successively connecting each component to, and disconnecting it from, the battery. The microprocessor compares the battery current draw of each component, when energized, with the associated battery current draw limits. An alarm is provided when a battery current draw is outside the associated draw limits, with the alarm identifying the associated component.

Abstract: A tester for a vehicle engine idle air control system includes an air bypass valve operated by a solenoid which receives a pulse width modulated signal to control the degree of opening of the valve. The tester is inserted in the vehicle wiring harness and includes a manually controlled pulse width modulator for generating a test voltage to the solenoid. A switch is connected within the tester to switch between engine computer control or manual modulator control of the solenoid. A bar graph display monitors the voltage supplied to the solenoid to indicate the magnitude thereof. The bar graph display also indicates the occurrence of short or open circuits.

Abstract: A method of operating a transport refrigeration unit having electrical control which includes a display, including the steps of detecting the occurrence of predetermined events in the transport refrigeration unit, and classifying at least certain of them into first, second and third categories of fault conditions, and into a fourth category related to maintenance associated events. When a first category fault occurs, the unit is shut down, a visual alarm is flashed, and the nature of the fault is immediately identified. When a second category fault occurs, a visual alarm is steadily energized, and the nature of the fault if immediately identified. When third category faults and fourth category events occur, they are stored and periodically displayed, with the display respectively identifying the nature of the fault and the type of maintenance event.

Abstract: An apparatus for monitoring current through a lamp circuit that uses a series resistance shunt in the circuit with one end being connected to a current source and the second end being connected to the lamp. The circuitry includes a comparator that is connected across the shunt and has a threshold switching voltage such that a voltage across the shunt that is larger than the threshold voltage will switch the comparator on (as in the case where the lamp is not functioning) and a voltage across the shunt that is smaller than the threshold voltage (as in the case where the lamp is in the circuit and functioning) will switch the comparator off. In a preferred embodiment, the shunt is actually a portion of the printed circuit board trace.

Abstract: A tractor-trailer light system test circuit comprises: a first multi-pin plug; a plurality of circuit breakers; a second multi-pin plug; an audible buzzer; an ON-OFF push button switch; a first LED, a second LED, and a third LED; a plurality of resistors; a first resistor, a secon resistor, and a third resistor; a first test plug and a second test plug; and a first plurality of light emitting diodes, a second plurality of light emitting diodes, and a third plurality of light emitting diodes.

Abstract: An automotive electrical system including a wiring harness incorporates a dedicated test line passing through critical connectors and components for allowing detection and isolation of improperly connected connectors. The dedicated test line can feed through expansion connectors, termination connectors, and junction blocks. A respective impedance is connected between the dedicated test line and ground at each respective connector. Connector fault detection and isolation is achieved by measuring the total impedance presented at the beginning of the test line. The measured impedance uniquely identifies the locations of any improperly connected connectors.

Abstract: An electronic motor control system is taught herein which utilizes a speedometer testing circuit. The (electronic) speedometer/odometer of a vehicle is tested, with the testing device being interconnected with the (input) terminals of the speedometer, exclusive of whether the speedometer is installed or removed from the vehicle. The testing device is utilized without vehicle input to the speedometer in order to determine whether the speedometer can produce an expected signal upon testing thus determining whether the speedometer is functional or not. The testing circuit has a self-contained power supply, is compact in size, and lightweight, thereby insuring complete mobility of the testing unit and dual application of the circuit to both installed and disengaged speedometer and odometer mechanisms.

Abstract: An auto electric tester has been provided that is simpler in construction, easier to manufacture and can expedite the location of several electrical problems more easily than all known prior art. The tester comprises a casing, circuitry mounted within the casing, four electrical conductors extending from the casing and connected to the circuitry.

Abstract: An electrical connector for use in a vehicular smart power multiplexing network is disclosed. Smart power connectors provide for connections between the power network and the various peripheral devices and components in a vehicle. The connector is comprised of two body portions which are electrically coupled when closed. The first body portion includes three connectors for electrical connection to the power network and the peripheral devices and components. The second body portion includes the smart power circuit and heat sink for dissipating heat generated by the power stage components. The smart power connector also has diagnostic capabilities for detecting device and component load failures.

Abstract: A test module incorporating a unique diagnostic circuit for monitoring the magnitude of electrical parameters existing between an electrical driver such as the electronic control module (ECM) of an automotive vehicle and an electrical load in the vehicle's electrical system. The circuit employs a visual indicator connected to a point adjacent the driver to provide a visual signal when the voltage at the point of connection lies within a predetermined range with respect to electrical ground. An additional visual indicator, separate from the first, is connected to a point adjacent to the electrical load, and provides a visual signal when the voltage at its point of connection lies within a predetermined range with respect to electrical ground. A third visual indicator is connected between the driver and load, and provides a visual signal in response to current flowing between the driver and load.

Abstract: A device for tracing preferably short-circuiting in electric systems.When tracing short-circuiting it is desirable that voltage and current will have normal values immediately after elimination thereof, for instance by contact. This object has been achieved in that an oscillator (23) limits the current at the output (19) to near 0 A as long as short-circuiting remains.When the short-circuiting ceases this is detected by a unit of sensitivity (24) and, as a result of this, the oscillation stops and preset current and voltage levels are entered immediately and automatically.

Abstract: An apparatus for testing a cross-coil instrument having a pointer, a sensor for sensing a condition to produce a sensor signal indicative of the sensed condition, and a converter coupled to the sensor for converting the sensor signal to a deflection of the pointer. The apparatus comprises a fault detector coupled to the sensor for detecting a disconnection fault to produce a command signal, and a test signal generator responsive to the command signal for generating a predetermined test signal to the converter, thereby moving the pointer to a predetermined position. The operation accuracy of the cross-coil instrument may be checked from the difference between the actual and predetermined pointer positions when a connector provided in a signal line between the sensor and the fault detector is pulled out.

Abstract: A testing device for determining, in an automobile electrical system, the integrity and continuity of the power input circuitry to a mobile telephone installation, comprises a pair of body sections that are joined to form a hollow interior region. Electrical contact pins are mounted in bores through an interior wall integral with one of the body sections. The contact pins are arranged to contact terminals, connected to the battery, ignition, and ground circuits of the automobile electrical system, at the junction between the electrical system and the telephone installation. The battery and ignition pins are connected to the input node of a red and a yellow LED, respectively. The output nodes of the LEDs are spliced together and connected to the ground pin. The LEDs are press-fit into an opening through a grommet. The grommet is press-fit and sealed onto the open end of one of the body sections.

Abstract: A method of testing electrical continuity and so forth of distributing cables which are rigged in a plurality of mutually coupled vehicles of an electric, diesel or steam railroad train for electrically connecting monitored apparatus in the vehicles to monitors installed for watching and checking such monitored apparatus.

Abstract: A test module incorporating a unique diagnostic circuit for monitoring the magnitude of electrical parameters existing between an electrical driver such as the electronic control module (ECM) of an automotive vehicle and an electrical load in the vehicle's electrical system. The circuit employs a visual indicator connected to a point adjacent the driver to provide a visual signal when the voltage at the point of connection lies within a predetermined range with respect to electrical ground. An additional visual indicator, separate from the first, is connected to a point adjacent to the electrical load, and provides a visual signal when the voltage at its point of connection lies within a predetermined range with respect to electrical ground. A third visual indicator is connected between the driver and load, and provides a visual signal in response to current flowing between the driver and load.

Abstract: A wiring state detecting device for vehicle has an operation control device for supplying power to apparatuses mounted on a vehicle, and operating the apparatuses, a battery mounted on the vehicle, a power supply line for connecting the operation control device to the battery, a wiring state detecting circuit provided in the operation control device for detecting the variation of electric current of the power supply line, discriminating the wiring state between the apparatuses and the operation control device based on the detected variation of electric current, and superposing the discriminated result on the power supply line as wiring state data, and an indicating device provided in the power supply line for receiving and indicating the wiring state data.