Abstract: A motor vehicle accessory control is capable of reversibly activating a DC motor to operate a vehicle door lock, window, sun roof or similarly operated device through a relay controlled H-switch arrangement. The control is provided with an automatic control circuit in a module having input and output terminals but only a single power terminal, which provides either positive power or ground to the module. The opposite power connections are made from the module through the activating relay coils of the H-switch motor drive circuit. A manual switch may be provided for alternative manual reversible activation of the relays; and the circuit provides priority of manual over automatic operation. Neither the manual switch nor the module circuit is capable of activating both relays simultaneously; therefore, a reliable power connection is always available for the module through at least one of the relay activating coils.

Abstract: A method of measuring and indicating a level of natural gas fuel in a storage tank of a motor vehicle, comprising the steps of determining a temperature of the natural gas, determining a pressure of the natural gas, retrieving from a look-up table, responsive to the determined temperature and pressure, a signal representative of a percentage that the tank is full of the natural gas, determining a gauge command responsive to the signal, and driving the gauge according to the determined command.

Abstract: A headlamp system provides for the high beam headlamp filaments to be connected in series across the supply voltage for half voltage energization in daytime running lamp operation when the ignition switch is closed, a DRL enabling switch is open and the headlamp switch is not in a headlamp on condition. In normal high beam headlamp operation, the high beam filaments are connected across the supply voltage in parallel for full voltage energization. The DRL enabling switch may be a park brake switch. The headlamp switch may have a fog lamp energizing condition to energize fog lamps; and the system permits such energization when the headlamps are connected in series but not when they are connected in parallel in normal high beam operation. A circuit is provided to sense when one of the high beam filaments is burned out and latch the daytime running light operation off with a signal to the vehicle operator.