GM Service Manual Online
For 1990-2009 cars only

Symptom

Procedure

Brake and center high mount stop lamp (CHMSL) inoperative

Go to Chart 1.

Center high mount stop lamp (CHMSL) inoperative, stop lamps OK

  1. Remove the CHMSL connector.
  2. Probe terminal circuit 20, LT BLU with a test light-to-ground.
  3. Apply brakes.
  4. • Bulb does not light -- open circuit 20 between left IPFB and CHMSL connector.
    • Bulb lights -- faulty bulb or open circuit 650. 450 sedan or 650 wagon.

Only one brake lamp does not operate.

Inspect bulb and related wiring for affected stop lamp.

Turn lamps do not operate, hazard lamps OK.

Go to Chart 2.

Hazard lamps do not operate, turn lamps OK.

Go to Chart 3.

Left turn indicator inoperative

Check bulb. If OK -- open circuit 14 between left IPFB.

Right turn indicator inoperative

Check bulb. If OK, open circuit 15 between left IPFB.

Park, marker and tail lamps inoperative

  1. Connect Tech 2.
  2. Turn head lamp switch to PARK position.
  3. Observe park lamp input on Tech 2.
  4. •  Input ON -- open circuit 9 between left IPFB and lamps
    • Input not ON -- disconnect headlamp connector. Connect a fused jumper between circuit 240, ORN and circuit 9, BRN.
       - Input on the Tech 2 changes to ON -- faulty connections or headlamp switch.
       - Input on the Tech 2 does not change to ON -- open circuit 9 between headlamp switch and left IPFB.

Both license lamps inoperative

Open circuit 9 between left IPFB and lamps

Both back-up lamps inoperative

Go to Chart 4.

One back-up lamp inoperative

Inspect related bulb and wiring.

Back-up lamps are always ON.

  1. Inspect adjustment of transaxle range switch (automatic) or back-up lamp switch (manual).
  2. If OK, circuit 240 shorted to B+, or faulty transaxle range switch (auto) or back-up lamp switch (manual).

Chart 1 - Brake Center High Mount Stop Lamp (CHMSL) Inoperative


Object Number: 890212  Size: FP

Chart 2 - Turn Lamps Do Not Operate - Hazard Lamps OK


Object Number: 898579  Size: FP

Chart 3 - Hazard Lamps Inoperative - Turn Lamps OK


Object Number: 898583  Size: FP

Chart 4 - Left Hand and Right Hand Back-Up Lamps Are Inoperative


Object Number: 890235  Size: FP