GM Service Manual Online
For 1990-2009 cars only

Test Description

The number below refers to the step number on the diagnostic table.

  1. Bulb test--Clip 1 end of a jumper wire to the negative battery terminal. Clip the other end of the jumper wire onto 1 end of the bulb. Take the end of the bulb without the jumper attached and touch it to the positive battery terminal.

Step

Action

Values

Yes

No

1

  1. Remove the interior courtesy lamp bulb and inspect the filament.
  2. If the filament is not broken, test the bulb using the vehicle's battery and a jumper wire.

Does the bulb pass the visual and physical checks?

--

Go to Step 3

Go to Step 2

2

Replace the bulb.

Is the repair complete?

--

System OK

--

3

  1. Reinstall the interior courtesy lamp bulb.
  2. Inspect fuse EF11.

Is either fuse EF11 open?

--

Go to Step 4

Go to Step 5

4

  1. Inspect for a short circuit and repair it, if necessary.
  2. Replace the fuse.

Is the repair complete?

--

System OK

--

5

  1. Disconnect the interior courtesy lamp electrical connector.
  2. Measure the voltage at connector terminal 3.

Does the voltage at connector terminal 3 measure within the specified range?

11-14 V

Go to Step 6

Go to Step 7

6

Repair the open circuit between fuse EF11 and the interior courtesy lamp terminal 3.

Is the repair complete?

--

System OK

--

7

Use an ohmmeter to measure the resistance between the interior courtesy lamp connector 1 and ground on the harness side.

Is the resistance equal to the specified value?

0 Ω

Go to Step 8

Go to Step 9

8

Replace the interior courtesy lamp switch assembly.

Is the repair complete?

--

System OK

--

9

Repair the ground circuit for the interior courtesy lamp.

Is the repair complete?

--

System OK

--