GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Exterior Lights Schematics

Connector End View Reference: Lighting Systems Connector End Views or Computer/Integrating Systems Connector End Views in Computer/Integrating Systems

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

  1. Turn ON the ignition, with the engine OFF.
  2. Place the gear selector in the PARK position.
  3. Place the headlamp switch in the PARK position.

Do the park lamps operate properly?

Go to Step 3

Go to Park Lamps Inoperative

3

  1. Place the headlamp switch in the LH PARK position.
  2. Place the headlamp switch in the RH PARK position.

Do the position lamps operate properly?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 4

4

Are both position lamps inoperative?

Go to Step 5

Go to Step 10

5

  1. With a scan tool, select the Position Lamp Relay from the dash integration module (DIM) Special Functions Output Controls.
  2. Command the STANDING LP Relay ON and OFF.

Do you hear a click when you command the STANDING LP Relay ON and OFF?

Go to Step 9

Go to Step 6

6

  1. Turn OFF the ignition.
  2. Disconnect the STANDING LP Relay.
  3. Turn ON the ignition, with the engine OFF.
  4. Connect a test lamp between the battery positive voltage circuit of the STANDING LP Relay coil and a good ground.

Does the test lamp illuminate?

Go to Step 7

Go to Step 26

7

Connect a test lamp between the battery positive voltage circuit of the STANDING LP Relay coil and the control circuit of the STANDING LP Relay.

Without commanding the relay on, does the test lamp illuminate?

Go to Step 18

Go to Step 8

8

Command the STANDING LP Relay ON.

Does the test lamp illuminate?

Go to Step 23

Go to Step 17

9

  1. Turn OFF the ignition.
  2. Disconnect the STANDING LP Relay.
  3. Turn ON the ignition, with the engine OFF.
  4. Connect a test lamp between the battery positive voltage circuit of the STANDING LP Relay switch and a good ground.

Does the test lamp illuminate?

Go to Step 23

Go to Step 30

10

  1. Disconnect the inoperative position lamp.
  2. Connect a test lamp between the supply voltage circuit of the position lamp and a good ground.
  3. Place the headlamp switch in the appropriate position.

Does the test lamp illuminate?

Go to Step 11

Go to Step 12

11

Connect a test lamp between the supply voltage circuit of the position lamp and the ground circuit of the position.

Does the test lamp illuminate?

Go to Step 24

Go to Step 27

12

Command the POSN LP Relay ON and OFF by placing the headlamp switch in the appropriate position.

Do you hear a click when you command the POSN LP Relay ON and OFF?

Go to Step 15

Go to Step 13

13

  1. Turn OFF the ignition.
  2. Disconnect the appropriate POSN LP Relay.
  3. Turn ON the ignition, with the engine OFF.
  4. Connect a test lamp between the supply voltage circuit of the POSN LP Relay coil and a good ground.

Does the test lamp illuminate?

Go to Step 14

Go to Step 29

14

  1. Connect a test lamp between the supply voltage circuit of the POSN LP Relay coil and the control circuit of the POSN LP Relay.
  2. Place the headlamp switch in the appropriate position.

Does the test lamp illuminate?

Go to Step 22

Go to Step 20

15

  1. Turn OFF the ignition.
  2. Disconnect the appropriate POSN LP Relay.
  3. Turn ON the ignition, with the engine OFF.
  4. Connect a test lamp between the battery positive voltage circuit of the POSN Relay switch and a good ground.

Does the test lamp illuminate?

Go to Step 16

Go to Step 28

16

Connect a 15-amp fused jumper between the battery positive voltage circuit of the POSN Relay switch and the supply voltage circuit of the position lamp.

Does the position lamp illuminate?

Go to Step 22

Go to Step 19

17

Test for an open or high resistance in the control circuit of the STANDING LP Relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 36

Go to Step 25

18

Test for a short to ground in the control circuit of the STANDING LP Relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 36

Go to Step 25

19

Test for an open or high resistance in the supply voltage circuit of the position lamp. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 36

Go to Step 27

20

Test for an open or high resistance in the control circuit of the POSN LP Relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 36

Go to Step 21

21

Inspect for poor connections at the headlamp switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 36

Go to Step 31

22

Inspect for poor connections at the appropriate POS LP relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 36

Go to Step 32

23

Inspect for poor connections at the STANDING LP relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 36

Go to Step 33

24

Inspect for poor connections at the inoperative position lamp. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 36

Go to Step 34

25

Inspect for poor connections at the DIM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 36

Go to Step 35

26

Repair an open or high resistance in the battery positive voltage circuit of the STANDING LP Relay coil. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 36

--

27

Repair an open or high resistance in the ground circuit of the position lamp. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 36

--

28

Repair an open or high resistance in the battery positive voltage circuit of the POS LP Relay switch. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 36

--

29

Repair an open or high resistance in the supply voltage circuit of the POS LP Relay coil. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 36

--

30

Repair an open or high resistance in the battery positive voltage circuit of the STANDING LP Relay switch. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 36

--

31

Replace the headlamp switch. Refer to Headlamp Switch Replacement .

Did you complete the replacement?

Go to Step 36

--

32

Replace the appropriate POS LP relay. Refer to Relay Replacement in Wiring Systems.

Did you complete the replacement?

Go to Step 36

--

33

Replace the STANDING LP relay. Refer to Relay Replacement in Wiring Systems.

Did you complete the replacement?

Go to Step 36

--

34

Replace the inoperative position lamp.

Did you complete the replacement?

Go to Step 36

--

35

Replace the DIM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 36

--

36

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2