GM Service Manual Online
For 1990-2009 cars only

Test Description

Caution: Do not connect a jumper cable directly to the negative terminal of a discharged battery to prevent sparking and possible explosion of battery gases.

The numbers below refer to the step numbers on the diagnostic table.

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

Step

Action

Values

Yes

No

1

  1. Remove the luggage compartment 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 check?

--

Go to Step 3

Go to Step 2

2

Replace the bulb.

Is the repair complete?

--

System OK

--

3

  1. Reinstall the luggage compartment lamp bulb.
  2. Inspect fuse EF6 and F3.

Is any fuse blown?

--

Go to Step 4

Go to Step 5

4

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

Is the repair complete?

--

System OK

--

5

Inspect fuse EF6 and F3.

Is the voltage at fuse EF6 and F3 within the specified value?

11-14 V

Go to Step 7

Go to Step 6

6

Repair the open circuit between the battery and fuse EF6 or F3.

Is the repair complete?

--

System OK

--

7

  1. Disconnect the luggage compartment lamp electrical connector.
  2. Inspect the voltage at the OG/BK wire.

Is the voltage at the OG/BK wire within the specified value?

11-14 V

Go to Step 8

Go to Step 9

8

Repair the open circuit between fuse EF6 and the luggage compartment lamp.

Is the repair complete?

--

System OK

--

9

  1. Reconnect the luggage compartment lamp.
  2. Remove the luggage compartment lamp, tailgate switch.
  3. With a voltmeter, or test lamp, test the GY/BK wire at the luggage compartment lamp, tailgate, switch.

Is the voltage at the luggage compartment lamp switch within the specified value?

11-14 V

Go to Step 11

Go to Step 10

10

Repair the open circuit between the luggage compartment lamp and the luggage compartment lamp, tailgate switch.

Is the repair complete?

--

System OK

--

11

Use an ohmmeter to measure the resistance between ground and the BK wire at the luggage compartment, tailgate, lamp switch connector, harness side.

Is the resistance equal to the specified value?

0 ohms

Go to Step 12

Go to Step 13

12

Replace the luggage compartment lamp, tailgate, switch.

Is the repair complete?

--

System OK

--

13

Repair the ground circuit for the interior courtesy lamp.

Is the repair complete?

--

System OK

--