GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1998 🢒 Sonoma Pickup - 2WD 🢒 Body and Accessories 🢒 Lighting Systems 🢒 Headlight System Check

Step

Action

Normal Result(s)

Abnormal Result(s)*

1
  1. Turn the ignition switch to the RUN position.
  2. Ensure that the parking brake is released.
  3. Place a trouble light above the ambient light sensor in order to ensure that sufficient light reaches the ambient light sensor.
    • The daytime running lamps (DRLs) turn ON.
    • All of the exterior lamps are OFF.

2

Move the headlamp switch to the HEAD position.
    • The headlamps turn ON.
    • The daytime running lamps (DRLs) turn OFF.
    • All of the exterior lamps turn ON.
    • The interior lamps dim.

3
  1. Move the headlamp switch to the AUTO position.
  2. Remove the trouble light.
  3. Cover the ambient light sensor.
    • The headlamps turn ON within 1 minute and remain ON.
    • The daytime running lamps (DRLs) turn OFF.
    • All of the exterior lamps turn ON.
    • The interior lamps dim.

4

Move the multifunction switch to the HIGH BEAMS position.
    • The high beams turn ON.
    • All of the exterior lamps turn ON.

5
  1. Move the headlamp switch to the HEAD position.
  2. Activate the fog lamp switch.
    • The headlamps turn ON.
    • All of the exterior lamps turn ON.
    • The interior lamps dim.
    • The fog lamps turn ON.

6

Place the transmission in REVERSE.

The backup lamps turn ON.

Backup Lamp System Check

7

Open the driver's door or the passenger door.

The interior lamps turn ON.

Interior Lamps System Check

* Refer to the appropriate symptom diagnostic table for the applicable abnormal result.