Abstract: An apparatus (16) for diagnosing faults in the electrical circuit of a motor vehicle which has a microprocessor (90) connected to a wiring harness (10) of a vehicle for controlling selected operations of the vehicle as a diagnostic microprocessor (22) which is coupled to the vehicle microprocessor (90) and wiring harness (10) by way of a multipin connector (14) and either an autotest circuit (44) or a manual breakout box (42) and reference probe (18). The microprocessor (22) also has a further test probe (20) for connection to the various terminals in the wiring harness (10). A plugin module (28) stores information particular to the vehicle and the test and the diagnostic microprocessor (22) monitors the vehicle microprocessor (90) and interprets any fault signals received from this using the information in the plugin module (28) to carry out a diagnostic test of the vehicle wiring harness (10) to locate the fault.

Abstract: A vehicle wheel alignment measurement system includes four infra-red emitter-detector units fixed by clamps to the vehicle wheels. Each unit includes a beacon and a rotatable detector coaxial with the beacon and driven by a motor. Angular rotation of the detector is sensed and signals from the four units are analyzed by a signal processing computer to give absolute position and relative angular measurements of the four wheels.