Lighting and Horns: Description and Operation
GENERAL INFORMATIONNS vehicles use lighting on the interior and exterior of the vehicle for illuminating and indicating purposes. Lighting circuits are protected by fuses. Lighting circuits require an overload protected power source, on/off device, lamps and body ground to operate properly Plastic lamps require a wire in the harness to supply body ground to the lamp socket. Replace sockets and bulbs that are corroded.
Some of the interior and exterior lighting functions are governed by the body controller. The headlamp, dome, and the door ajar switches provide signals to the body controller. The body controller in turn activates relay(s) in order to provide either a ground or feed line to the appropriate lamp(s).
Wire connectors can make intermittent contact or become corroded. Before coupling wire connectors, inspect the terminals inside the connector. Male terminals should not be bent or disengaged from the insulator. Female terminals should not be sprung open or disengaged from the insulator. Bent and sprung terminals can be repaired using needle nose pliers and pick tool. Corroded terminals appear chalky or green. Corroded terminals should be replaced to avoid recurrence of the problem symptoms.
Begin electrical system failure diagnosis by testing related fuses in the fuse block and power distribution center. Verify that bulbs are in good condition and test continuity of the circuit ground.
SYSTEM OPERATION
The combination-flasher/DRL may be operated in its hazard warning mode either with or without the ignition circuit being active. However, in order to operate in the turn signal mode or the DRL mode, the ignition circuit must be completed to the module.
While the combination-flasher portion is idle, there is no current drawn through the module. The device does not become active in the turn signal or hazard warning modes until a signal ground circuit is supplied to either of the turn signal inputs or the hazard warning input. With the ignition OFF, there is no current drawn through the module.
While the ignition is ON, the front turn signal filaments are illuminated steadily thus providing the DRL function. The DRL function may be inhibited by applying a signal ground input from either the park brake circuit or the headlamp relay activation circuit.
Electronic Daytime Running Lights
Junction Block Terminal Pins:
The Combination Flasher/DRL is a module providing turn signal, hazard warning, and daytime running light functions (for Canadian vehicles), and has been designed with internal relays to take advantage of low current switching requirements in the vehicle. It is plugged into the junction block at positions three and four, where all wiring associated with its operation is terminated. The junction block is adjacent to and left of the steering column of the vehicle.
On vehicles built for use in the United States, only position four is used. Vehicles built for use in Canada utilize both positions three and four.
To gain access to the device, remove the lower steering column cover and knee blocker.