GM Service Manual Online
For 1990-2009 cars only

Step

Action

Values

Yes

No

1

Inspect the headlamps.

Do the headlamps work?

--

Go to Step 3

Go to Step 2

2

Repair the headlamps before continuing with this chart.

After the headlamps have been repaired, are the parking lamps and tail lamps still inoperative?

--

Go to Step 3

System OK

3

  1. Turn the parking lamps ON.
  2. Use a voltmeter to measure the voltage at the bulb socket positive terminal.

Does voltage at the bulb socket measure within the specified range?

11-14 V

Go to Step 4

Go to Step 7

4

Connect an ohmmeter between ground and the lamp socket negative terminal.

Is the resistance equal to the specified value?

0 ohms

Go to Step 6

Go to Step 5

5

Repair the ground circuit for the lamps.

Did you complete the repair?

--

System OK

--

6

Replace the faulty bulbs.

Did you complete the replacement?

--

System OK

--

7

Inspect fuses Ef23 and Ef28.

Are any of the fuses open?

--

Go to Step 8

Go to Step 9

8

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

Did you find and correct the condition?

--

System OK

--

9

  1. Turn the headlamps ON.
  2. Measure the voltage at fuses Ef23, left-side illumination lamp, and Ef28, right-side illumination lamp.

Does the voltage at the fuses measure within the specified range?

11-14 V

System OK

Go to Step 10

10

Repair the open circuit between the fuses Ef23 and Ef28 and the illumination lamps.

Did you complete the repair?

--

System OK

--