GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Did you perform the Interior Lamps Diagnostic System Check?

--

Go to Step 2

Go to Interior Lamps System Check

2

  1. Disconnect the lamp dimmer module connector.
  2. Turn the headlamp switch to the PARK position.
  3. Measure the voltage between terminal D and ground.

Is the voltage equal to the specified value?

B+

Go to Step 3

Go to Step 4

3

  1. Disconnect the lamp dimmer module connector.
  2. Place the dimmer switch in the HI position.
  3. Turn the headlamp switch to the PARK position.
  4. Measure the voltage between terminal B and ground.

Is the voltage equal to the specified value?

B+

Go to Step 5

Go to Step 9

4

  1. Remove the INST LPS fuse.
  2. Turn the headlamp switch to PARK.
  3. Measure the voltage between the INST LPS fuse cavity (CKT 9) and ground.

Is the voltage equal to the specified value?

B+

Go to Step 11

Go to Step 6

5

Connect a fused jumper between terminal D and terminal C.

Do the interior lamps light?

--

Go to Step 8

Go to Step 7

6

Repair an open in CKT 9. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Interior Lamps System Check

--

7

Repair an open in CKT 8. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Interior Lamps System Check

--

8

Replace the lamp dimmer module.

Is the repair complete?

--

Go to Interior Lamps System Check

--

9

  1. Disconnect the panel dimmer switch connector.
  2. Turn the headlamp switch to PARK.
  3. Measure the voltage between terminal C and ground.

Is the voltage equal to the specified value?

B+

Go to Step 10

Go to Step 11

10

Connect a fused jumper between terminal B and terminal C of the dimmer switch connector.

Do the interior lights illuminate?

--

Go to Step 12

Go to Step 13

11

Repair an open in CKT 32. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Interior Lamps System Check

--

12

Replace the IP dimmer switch.

Is the repair complete?

--

Go to Interior Lamps System Check

--

13

Repair an open in CKT 44. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Interior Lamps System Check

--