GM Service Manual Online
For 1990-2009 cars only

Step

Action

Values

Yes

No

Schematic Reference: Exterior Lights Schematics

Connector End View Reference: Component Connector End Views

1

Inspect fuses F3 and F14.

Is either fuse open?

--

Go to Step 2

Go to Step 3

2

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

Did you find and correct the condition?

--

System OK

--

3

  1. Turn the ignition ON.
  2. Measure the voltage at fuses F3 and F14.

Does the battery voltage available at both fuses F3 and F14 measure within the specified range?

11-14 V

Go to Step 4

Go to Step 7

4

  1. Turn the hazard switch ON.
  2. Remove each of the inoperative lamps from its socket.
  3. Test each lamp socket positive terminal with a voltmeter.

Does the battery voltage pulsing at the turn signal hazard lamp socket positive terminal measure within the specified range?

11-14 V

Go to Step 5

Go to Step 9

5

At each bulb socket, use an ohmmeter to test the ground circuit.

Is the resistance equal to the specified value?

0 Ω

Go to Step 6

Go to Step 8

6

Replace any faulty turn signal/hazard bulbs.

Did you complete the replacement?

--

System OK

--

7

Repair the power supply circuit to fuses.

Did you complete the repair?

--

System OK

--

8

Repair the open ground wires.

Did you complete the repair?

--

System OK

--

9

  1. Turn ON the hazard lamp switch.
  2. Test the blinker unit connector terminal 49a with a voltmeter.

Does the battery voltage pulsing at the blinker unit terminal 49a measure within the specified range?

11-14 V

Go to Step 15

Go to Step 10

10

  1. Turn ON the hazard lamp switch.
  2. Test the blinker unit connector terminal 49 with a voltmeter.

Does the battery voltage available at the blinker unit terminal 49 measure within the specified range?

11-14 V

Go to Step 11

Go to Step 14

11

  1. Disconnect the blinker unit from the connector.
  2. Use an ohmmeter to check between ground and the connector for terminal 31 of the blinker unit.

Is the resistance equal to the specified value?

0 Ω

Go to Step 13

Go to Step 12

12

Repair the blinker unit ground connection.

Did you complete the repair?

--

System OK

--

13

Replace the faulty blinker unit.

Did you complete the replacement?

--

System OK

--

14

  1. Disconnect the hazard lamp switch connector.
  2. Test for voltage at terminal 8.
  3. Turn the ignition ON.
  4. Test for voltage at terminal 10.

Does the battery voltage available at both terminals measure within the specified range?

11-14 V

Go to Step 15

Go to Step 16

15

  1. Remove the hazard lamp switch.
  2. Turn the hazard lamp switch OFF.
  3. Test for continuity between terminals 7 and 10.
  4. Turn the hazard lamp switch ON.
  5. Test for continuity between terminals 7 and 8.

Do both tests show the specified value?

0 Ω

Go to Step 18

Go to Step 17

16

  1. Remove the hazard lamp switch.
  2. Turn the hazard lamp switch ON.
  3. Use an ohmmeter to check for continuity between terminals 5, 6, and 9.

Does the continuity between terminals 5, 6, and 9 equal the specified value?

0 Ω

Go to Step 19

Go to Step 17

17

Replace the faulty hazard lamp switch.

Did you complete the replacement?

--

System OK

--

18

Repair the open circuit between the hazard lamp switch terminal 7 and the blinker unit terminal 49.

Did you complete the repair?

--

System OK

--

19

Repair the open circuit between the hazard lamp switch and the fuses F3 or F14.

Did you complete the repair?

--

System OK

--