Turn Signals: Description and Operation
SYSTEM OPERATIONCombination Flasher
The turn signal flasher and the hazard warning flasher are combined into one unit called a combination flasher (combo-flasher). An inoperative or incomplete turn signal circuit will result in an increase in flasher speed.
The flasher is mounted to the back side of the multi-function switch.
Exterior Lamps
To turn lamps ON:
- Parking lamps, using left stalk turn headlamp switch to the first detent
- Headlamps, turn switch to second detent
- Headlamp beam select, from low beam to high beam or high to low, pull left stalk towards steering wheel. The ignition switch must be in the RUN position for the instrument panel high beam indicator to light.
- Headlamp optical horn, pull left stalk towards steering wheel, headlamps will stay ON as long as stalk is held.
- Fog lamps, pull switch outward with headlamps on low beam
- Panel dimmer, rotating dimmer switch regulates density of the instrument panel illumination. There are nine detentes (steps) of density Detent 1 is full brightness and each detent thereafter is lower. Testing the dimmer switch using the continuity test, the resistance value is measured for each detent. Detents 3 through 8 are measured in equal graduations, up or down and referred to as linear. Example: if detent 3 was 5 Ohms and detent 4 was 7 Ohms detent 5 should be 9 Ohms.
Hazard Warning System
The hazard warning system is actuated by a push button located on the top of the steering column between the steering wheel and the instrument panel. The hazard switch is identified with a double triangle on top of the button. Push and release the button to turn the hazard function ON or OFF The button will move out from the steering column in the ON position and will remain in toward the column in the OFF position.
CIRCUIT OPERATION
Power for the turn signals flows from the Power Distribution Center (PDC) to the ignition switch on circuit A1. The A1 circuit is protected by a 20 Amp fuse located in cavity 8 of the PDC. With the key in the ACCESSORY or RUN position, the ignition switch connects voltage from the A1 circuit to the A31 circuit.
Circuit A31 connects to the junction block and powers fuse 15. This is a 10 Amp fuse. From the fuse, circuit F13 supplies voltage to the combination flasher. The F13 circuit also supplies power to the windshield wipers and the rear window defogger relay.
Circuit A15 also supplies voltage to the combination flasher. This circuit is HOT at all times and is protected by a 20 Amp fuse located in cavity 6 of the PDC.
The L32 circuit connects between the combination flasher and the turn signal portion of the multi-function switch. Circuit L32 connects to a BUS bar internal to the switch that powers the turn signals and the hazard flasher.
Right Turn Signal
When the operator selects the right turn signal, the multi-function switch connects power from circuit L32 to circuit L60. Circuit L60 supplies power for the front lamp and provides an input to the combined rear lighting module. This circuit also splices and supplies power to the instrument cluster indicator lamp.
Circuit L62 connects from the combined rear lighting module to the right rear lamps.
Ground for the rear lamp is provided on circuit Z1 and terminates at the left rear wheel well. The ground for the front lamp is provided on circuit Z1 and terminates at the right frame rail.
Left Turn Signal
When the operator selects the left turn signal, the multi-function switch connects power from circuit L32 to circuit L61. Circuit L61 supplies power for the front lamp and also provides an input to the combined rear lighting module. This circuit also splices and supplies power to the instrument cluster indicator lamp.
Circuit L63 connects from the combined rear lighting module to the left rear lamps.
Ground for the rear lamp is provided on circuit Z1 and terminates at the left rear wheel well. The ground for the front lamp is provided on circuit Z1 and terminates at the left strut tower.