Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSCHEVROLET2003TRAILBLAZER 4.2 S, 4WDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 1317 (LIGHTING SYSTEMS)DIAGNOSTIC INFORMATION AND PROCEDURESAUTOMATIC LAMP CONTROL INOPERATIVE
2003 Chevrolet TrailBlazer 4.2 S, 4WD
Automatic Lamp Control Inoperative
2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Automatic Lamp Control Inoperative
WARNING: This page is about a different car, the 2004 Pontiac Vibe. However, it is still accessible from the selected car via links, so may be relevant.
Automatic Lamp Control Inoperative
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Exterior Lights Schematics | |||
| 1 | Did you review the Lighting System Description and Operation and perform the necessary inspections? | Go to Step 2 | Go to Symptoms - Lighting Systems |
| 2 | Verify the parking lamps are not turning on and off in light and dark conditions. Does the system operate normally? |
Go to Testing for Electrical Intermittents | Go to Step 3 |
| 3 | With the ambient light sensor and the daytime running lamps control module disconnected. Test between cavity 1 of the ambient light sensor harness connector and cavity 18 of the DRL control module harness connector for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? |
Go to Step 8 | Go to Step 4 |
| 4 | Test between cavity 3 of the ambient light sensor harness connector and cavity 16 of the DRL control module harness connector for an open or high resistance. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
Go to Step 8 | Go to Step 5 |
| 5 | Test between cavity 4 of the ambient light sensor harness connector and cavity 17 of the DRL control module harness connector for an open or high resistance. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
Go to Step 8 | Go to Step 6 |
| 6 | Replace the Ambient Light Sensor with a know good Sensor. Refer to Daytime Running Lamps (DRL) Ambient Light Sensor Replacement . Did you correct the condition? |
Go to Step 8 | Go to Step 7 |
| 7 | Replace the Daytime Running Lamp Control Module. Refer to Daytime Running Lights (DRL) Control Module Replacement . Did you correct the condition? |
Go to Step 8 | - |
| 8 | Operate the system in order to verify the repair. Did you correct the condition? |
System OK | Go to Step 3 |
RENDER: 1.0x
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.