GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Headlights/Daytime Running Lights (DRL) 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. Move the gear selector out of the PARK position.
  3. Verify that the headlamp switch is in the OFF position.
  4. Expose the sunload sensor to a bright incandescent lamp.
  5. Wait more than 3 seconds.

Do the daytime running lamps (DRL) headlamps operate properly?

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

Go to Step 3

3

  1. With a scan tool, select from the Dash Integration Module (DIM) Special Functions Output Controls, the Daytime Running Lamps.
  2. Command the DRL relay ON and OFF.

Do you hear a click when you command the DRL relay ON and OFF?

Go to Step 6

Go to Step 4

4

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

Does the test lamp illuminate?

Go to Step 5

Go to Step 14

5

  1. Connect a test lamp between the battery positive voltage circuit of the DRL relay coil and the control circuit of the DRL relay.
  2. With a scan tool, command the DRL relay ON and OFF.

Does the test lamp turn ON and OFF with each command?

Go to Step 11

Go to Step 10

6

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

Does the test lamp illuminate?

Go to Step 7

Go to Step 15

7

Connect a 15-amp fused jumper between the battery positive voltage circuit of the DRL relay switch and the DRL supply voltage circuit.

Do the DRL headlamps illuminate?

Go to Step 11

Go to Step 8

8

  1. Turn OFF the ignition.
  2. Reconnect the DRL relay.
  3. Disconnect the DRL resistor.
  4. Turn ON the ignition with the engine OFF
  5. Connect a test lamp between the supply voltage circuit of the DRL resistor and a good ground.
  6. With a scan tool, command the DRL relay ON.

Does the test lamp illuminate?

Go to Step 9

Go to Step 16

9

  1. Connect a 15-amp fused jumper between the supply voltage circuit of the DRL resistor and the DRL resistor signal circuit.
  2. With a scan tool, command the DRL relay ON.

Do the DRL headlamps illuminate?

Go to Step 13

Go to Step 17

10

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

Did you find and correct the condition?

Go to Step 21

Go to Step 12

11

Inspect for poor connections at the DRL 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 21

Go to Step 19

12

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 21

Go to Step 20

13

Inspect for poor connections at the DRL resistor. 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 21

Go to Step 18

14

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

Did you complete the repair?

Go to Step 21

--

15

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

Did you complete the repair?

Go to Step 21

--

16

Repair the open in the supply voltage circuit of the DRL resistor. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 21

--

17

Repair the open or high resistance in the signal circuit of the DRL resistor . Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 21

--

18

Replace the DRL resistor.

Did you complete the replacement?

Go to Step 21

--

19

Replace the DRL relay. Refer to Relay Replacement in Wiring Systems.

Did you complete the replacement?

Go to Step 21

--

20

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 21

--

21

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2