GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

1

Did you perform the Lighting Systems Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

  1. Disconnect the turn/headlamp switch assembly connector C1.
  2. Test for an open in the ground circuit 150. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct an open?

System OK

Go to Step 3

3

Use a fused jumper in order to ground terminal 33 of the turn/headlamp switch connector C1.

Do the high beams light?

Go to Step 4

Go to Step 5

4

Replace the turn/headlamp switch assembly. Refer to Multifunction Turn Signal Lever Replacement - On Vehicle in Steering Wheel and Column.

Is the repair complete?

System OK

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5

Test for an open in CKT 1200 between the turn/headlamp switch assembly and each headlamp assembly. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

System OK

Go to Step 6

6

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

Did you find and correct the condition?

System OK

Go to Step 7

7

Replace the left and right headlamp bulbs. Refer to Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement .

Is the repair complete?

System OK

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