GM Service Manual Online
For 1990-2009 cars only

Daytime Running Lamps (DRL) Headlamps Always On Standard

Step

Action

Value(s)

Yes

No

1

Did you perform the Lighting Systems Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

Verify that the DRL headlamps are always on.

Do the DRL headlamps operate normally?

--

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

Go to Step 3

3

Use the Scan Tool to inspect for the following related Body Control Module (BCM) Data/ Input parameters and Output controls.

Refer to Scan Tool Data List in Body Control System for typical values and definitions.

    • Headlamp Ambient Light Sensor
    • Park Brake Switch
    • Auto Headlamps
    • Headlamp Relay Feedback
    • Daytime Running Lamps Relay
    • Headlamp Power Relay
    • Left Turn Signal
    • Right Turn Signal
    • High Beam Switch
    • Flash to Pass Switch

Did you find and correct a problem?

--

Go to Step 9

Go to Step 4

4

Remove the DRL relay from the underhood fuse block.

Do the daytime running lamps remain on?

--

Go to Step 5

Go to Step 6

5

Locate and repair a short to ground in CKT 711 (DK GRN/WHT) between the left headlamp high beam bulb and the underhood fuse block. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 9

--

6

  1. Make sure the Ignition Switch is in the OFF position.
  2. Remove the Headlamp Grounding Relay in the Body Relay Block.
  3. Disconnect the BCM connector C 1.
  4. Using the J 39200 Digital Multimeter (DMM), check for continuity to ground CKT 592 (LT GRN/BLK) at the BCM connector C 1, terminal A 11. Refer to Circuit Testing in Wiring Systems.

Is continuity present?

--

Go to Step 7

Go to Step 8

7

Locate and repair short to ground in CKT 592 (LT GRN/BLK). Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 9

--

8

Replace the DRL Relay.

Is the repair complete?

--

Go to Step 9

--

9

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 3

Daytime Running Lamps (DRL) Headlamps Always On Envoy/Diamond Edition 1SK

Step

Action

Value(s)

Yes

No

1

Did you perform the Lighting Systems Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

Verify that the DRL headlamps are always on.

Do the DRL headlamps operate normally?

--

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

Go to Step 3

3

Use the Scan Tool to inspect for the following related Body Control Module (BCM) Data/ Input parameters and Output controls.

Refer to Scan Tool Data List in Body Control System for typical values and definitions.

    • Headlamp Ambient Light Sensor
    • Park Brake Switch
    • Auto Headlamps
    • Headlamp Relay Feedback
    • Daytime Running Lamps Relay
    • Headlamp Power Relay
    • Left Turn Signal
    • Right Turn Signal
    • High Beam Switch
    • Flash to Pass Switch

Did you find and correct a problem?

--

Go to Step 9

Go to Step 4

4

Remove the DRL relay from the underhood fuse block.

Do the daytime running lamps remain on?

--

Go to Step 5

Go to Step 6

5

Locate and repair a short to power in CKT 1193 (LT GRN/BLK) between the right headlamp high beam bulb and the underhood fuse block. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 9

--

6

  1. Make sure the Ignition Switch is in the OFF position.
  2. Disconnect the BCM connector C 1.
  3. Using the J 39200 Digital Multimeter (DMM), check for continuity to ground CKT 592 (LT GRN/BLK) at the BCM connector C 1, terminal A 11. Refer to Circuit Testing in Wiring Systems.

Is continuity present?

--

Go to Step 7

Go to Step 8

7

Locate and repair short to ground in CKT 592 (LT GRN/BLK). Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 9

--

8

Replace the DRL Relay.

Is the repair complete?

--

Go to Step 9

--

9

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 3

Daytime Running Lamps (DRL) Headlamps Always On ZR2

Step

Action

Value(s)

Yes

No

1

Did you perform the Lighting Systems Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

Verify that the DRL headlamps are always on.

Do the DRL headlamps operate normally?

--

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

Go to Step 3

3

Use the Scan Tool to inspect for the following related Body Control Module (BCM) Data/ Input parameters and Output controls.

Refer to Scan Tool Data List in Body Control System for typical values and definitions.

    • Headlamp Ambient Light Sensor
    • Park Brake Switch
    • Auto Headlamps
    • Headlamp Relay Feedback
    • Daytime Running Lamps Relay
    • Headlamp Power Relay
    • Left Turn Signal
    • Right Turn Signal
    • High Beam Switch
    • Flash to Pass Switch

Did you find and correct a problem?

--

Go to Step 9

Go to Step 4

4

Remove the DRL (ZR2) relay.

Do the daytime running lamps remain on?

--

Go to Step 5

Go to Step 6

5

Locate and repair short to ground in CKT 525 (YEL). Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 9

--

6

  1. Make sure the Ignition Switch is in the OFF position.
  2. Disconnect the BCM connector C 1.
  3. Using the J 39200 Digital Multimeter (DMM), check for continuity to ground CKT 592 (LT GRN/BLK) at the BCM connector C 1, terminal A 11. Refer to Circuit Testing in Wiring Systems.

Is continuity present?

--

Go to Step 7

Go to Step 8

7

Locate and repair short to ground in CKT 592 (LT GRN/BLK). Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 9

--

8

Replace the DRL Relay.

Is the repair complete?

--

Go to Step 9

--

9

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 3