GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Did you perform the Lighting System Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

  1. Turn OFF the headlamp switch.
  2. Turn ON the ignition, with the engine OFF.
  3. With the scan tool, observe the headlamp switch input status.

Does the headlamp switch input status indicate OFF.

--

Go to Step 3

Go to Step 7

3

Test the low beam relay control circuit for a short to ground. Refer to Circuit Testing an Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 4

4

  1. Turn OFF the ignition switch.
  2. Disconnect the low beam relay.
  3. Turn ON the ignition, with the engine OFF.

Did the low beam headlights turn OFF?

--

Go to Step 5

Go to Step 10

5

Inspect for poor connections at the low beam relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 6

6

Replace the low beam relay. Refer to Wiring Repairs in Wiring Systems.

Did you complete the replacement?

--

Go to Step 14

--

7

  1. Turn OFF the ignition.
  2. Disconnect the headlamp switch.
  3. Turn ON the ignition, with the engine OFF.
  4. With the scan tool, observe the headlamp switch input status.

Does the headlamp switch input status indicate OFF.

--

Go to Step 8

Go to Step 11

8

Inspect for poor connections at the headlamp switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 9

9

Replace the headlamp switch. Refer to Headlamp Switch Replacement .

Did you complete the replacement?

--

Go to Step 14

--

10

Repair the short to power in the low beam headlamp circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 14

--

11

Test the headlamp switch input circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 12

12

Inspect for poor connections at the dash integration module (DIM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 13

13

Replace the DIM. Refer to Dash Integration Module Replacement in Body Control System.

Did you complete the replacement?

--

Go to Step 14

--

14

Operate the system in order to verify the repair.

Did you find and correct the condition?

--

System OK

Go to Step 2