Hazard Warning Lamps: Testing and Inspection

When diagnosing the turn signal or hazard warning circuits, remember that high generator output can burn out bulbs rapidly and repeatedly. If this is a problem on the vehicle being diagnosed, be certain to diagnose and repair the charging system as required. If the problem being diagnosed is related to a failure of the turn signals to automatically cancel following completion of a turn, inspect the multi-function switch for a faulty or damaged cancel actuator and inspect the turn signal cancelling cam lobes on the clockspring mechanism for damage or improper installation.

WARNING: ON VEHICLES EQUIPPED WITH AIRBAGS, DISABLE THE AIRBAG SYSTEM BEFORE ATTEMPTING ANY STEERING WHEEL, STEERING COLUMN, OR INSTRUMENT PANEL COMPONENT DIAGNOSIS OR SERVICE. DISCONNECT AND ISOLATE THE BATTERY NEGATIVE (GROUND) CABLE, THEN WAIT TWO MINUTES FOR THE AIRBAG SYSTEM CAPACITOR TO DISCHARGE BEFORE PERFORMING FURTHER DIAGNOSIS OR SERVICE. THIS IS THE ONLY SURE WAY TO DISABLE THE AIRBAG SYSTEM. FAILURE TO TAKE THE PROPER PRECAUTIONS COULD RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL INJURY.

1. Turn the ignition switch to the ON position. Actuate the turn signal switch or the hazard warning switch. Observe the turn signal indicator lamp(s) in the instrument cluster. If the flash rate is very high, check for a turn signal bulb that is not lit or is very dimly lit Repair the circuits to that lamp or replace the faulty bulb, as required. If the turn signal indicator(s) fail to light, go to Step 2.
2. Turn the ignition switch to the OFF position. Check the turn signal fuse (Fuse 12 - 10 ampere) in the Junction Block (JB) and/or the hazard warning fuse (Fuse 20 - 15 ampere) in the Power Distribution Center (PDC). If OK, go to Step 3. If not OK, repair the shorted circuit or component as required and replace the faulty fuse(s).
3. Check for battery voltage at the hazard warning fuse (Fuse 20 - 15 ampere) in the PDC. If OK, go to Step 4. If not OK, repair the open fused B(+) circuit between the PDC and the battery as required.
4. Turn the ignition switch to the ON position. Check for battery voltage at the turn signal fuse (Fuse 12 - 10 ampere) in the JB. If OK, go to Step 5. If not OK, repair the open fused ignition switch output (accessory/run) circuit between the JB and the ignition switch as required.
5. Turn the ignition switch to the OFF position. Disconnect and isolate the battery negative cable. Remove the combination flasher from its wire harness connector and replace it with a known good unit. Connect the battery negative cable. Test the operation of the turn signal and hazard warning systems. If OK, discard the faulty combination flasher. If not OK, remove the test flasher and go to Step 6.
6. Turn the ignition switch to the ON position. Check for battery voltage at the fused ignition switch output (accessory/run) circuit cavity in the instrument panel wire harness connector for the combination flasher. If OK, go to Step 7. If not OK, go to Step 9.
7. Turn the ignition switch to the OFF position. Place the hazard warning switch in the ON position. Check for battery voltage again at the fused B(+) circuit cavity in the instrument panel wire harness connector for the combination flasher. If OK, go to Step 8. If not OK, go to Step 9.
8. Disconnect and isolate the battery negative cable. Check for continuity between the ground circuit cavity of the instrument panel wire harness connector for the combination flasher and a good ground. There should be continuity. If OK, go to Step 9. If not OK, repair the open ground circuit to ground as required.
9. Disconnect the instrument panel wire harness connector from the left multi-function switch connector receptacle. Check for continuity between the flasher output circuit cavities in the instrument panel wire harness connector for the combination flasher and in the instrument panel wire harness connector for the left multi-function switch. There should be continuity. If OK, go to Step 10. If not OK, repair the open flasher output circuit between the combination flasher and the left multi-function switch as required.
10. Check for continuity between the hazard flasher select signal circuit cavities in the instrument panel wire harness connector for the combination flasher and in the instrument panel wire harness connector for the left multi-function switch. There should be continuity. If OK, test the left multi-function switch. (Refer to LAMPS/ LIGHTING - EXTERIOR/LEFT MULTI-FUNCTION SWITCH - DIAGNOSIS AND TESTING). If not OK, repair the hazard flasher select signal circuit between the combination flasher and the left multi-function switch as required.