Daytime Running Lamps (DRL) Headlamps Inoperative. Chevrolet Blazer

For 1990-2009 cars only

Makes 🢒 Chevrolet 🢒 2000 🢒 Blazer - 4WD 🢒 Body and Accessories 🢒 Lighting Systems 🢒 Daytime Running Lamps (DRL) Headlamps Inoperative

Daytime Running Lamps (DRL) Headlamps Inoperative Standard

Step

Action

Value(s)

Yes

Did you perform the Lighting Systems Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

Verify that the DRL headlamps are inoperative.

Do the DRL headlamps operate normally?

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

Go to Step 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 10

Go to Step 4

Turn the headlamp switch to the HEAD position.

Do the headlamps operate properly in the LO position?

Go to Step 5

Go to Headlamps Inoperative - Low Beams

Turn the headlamp dimmer switch to the HI position.

Do the headlamps operate properly in the HI position?

Go to Step 6

Go to Headlamps Inoperative - High Beams

If the vehicle is equipped with fog lamps turn the Fog Lamp switch to the ON position.

Do the fog lamps operate properly?

Go to Step 7

Go to Fog Lamps Inoperative - All

With the key in RUN,park brake off, engine off, and the Headlamp Switch in the AUTO position, remove the DRL Relay from the Underhood Fuse Block.
Use a J 39200 Digital Multimeter (DMM) to check for continuity to ground from terminal 86 at the DRL Relay connector in the Underhood Fuse Block. Refer to Circuit Testing in Wiring Systems.

Is continuity present?

Go to Step 9

Go to Step 8

Locate and repair the open or high resistance in CKT 592 (LT GRN/BLK). Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to Step 10

Replace the DRL Relay.

Is the repair complete?

Go to Step 10

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 Inoperative Envoy/Diamond Edition 1SK

Step

Action

Value(s)

Yes

Did you perform the Lighting Systems Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

Verify that the DRL headlamps are inoperative.

Do the DRL headlamps operate normally?

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

Go to Step 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

•	High Beam Switch

•	Flash to Pass Switch

Did you find and correct a problem?

Go to Step 11

Go to Step 4

Turn the headlamp switch to the HEAD position.

Do the High beam headlamps operate properly?

Go to Step 5

Go to Headlamps Inoperative - High Beams

Inspect the IGN E 10A fuse in the Underhood Fuse Block.

Is the fuse open?

Go to Step 6

Go to Step 8

Remove the DRL Relay from the Underhood Fuse Block.
Use a J 39200 Digital Multimeter (DMM) to check for continuity to ground at terminal 2 of the DRL Relay connector in the Underhood Fuse Block. Refer to Circuit Testing in Wiring Systems.

Is continuity present?

Go to Step 7

Go to Step 10

Repair the short to ground in CKT 639 (PNK) or the associated components. Refer to Wiring Repairs in Wiring Systems and

IGN E Fuse and A/C Compressor, Rear Defogger, DRL Relays

Power and Grounding Components
B/U LP, TRL B/U and BTSI Fuses (Automatic Transmission)
TURN, SIR and GAUGES Fuses
Power and Grounding Connector End Views
Ign RUN and START Bus Bar
for more information.

Is the repair complete?

Go to Step 11

With the key in RUN, engine off, and the Headlamp Switch in the AUTO position, check for continuity to ground from terminal 1 at the DRL Relay connector in the Underhood Fuse Block. Refer to Circuit Testing in Wiring Systems.

Is continuity present?

Go to Step 10

Go to Step 9

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

Is the repair complete?

Go to Step 11

Replace the DRL Relay.

Is the repair complete?

Go to Step 11

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 Inoperative ZR2

Step

Action

Value(s)

Yes

Did you perform the Lighting Systems Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

Verify that the DRL headlamps are inoperative.

Do the DRL headlamps operate normally?

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

Go to Step 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

•	High Beam Switch

•	Flash to Pass Switch

Did you find and correct a problem?

Go to Step 13

Go to Step 4

Turn the headlamp switch to the HEAD position.

Do the low beam headlamps operate properly?

Go to Step 5

Go to Headlamps Inoperative - Low Beams

With the key in RUN and engine off, remove the DRL Relay (ZR2).
Use a J 39200 Digital Multimeter (DMM) to check for voltage at terminal 2 of the DRL Relay connector. Refer to Circuit Testing in Wiring Systems.

Is the specified voltage present?

B+

Go to Step 8

Go to Step 6

Inspect for open, high resistance or short to ground in CKT 639 (PNK). Refer to Circuit Testing in Wiring Systems.

Was a problem found?

Go to Step 7

Go to Step 11

Repair open, high resistance or short to ground in CKT 639 (PNK). Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to Step 13

With the Headlamp Switch in the AUTO position, use the J 39200 DMM to check for continuity to ground from terminal 1 at the DRL Relay connector. Refer to Circuit Testing in Wiring Systems.

Is continuity present?

Go to Step 10

Go to Step 9

Locate and repair open or high resistance in CKT 592 (LT GRN/BLK). Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to Step 13

Reinstall the DRL (ZR2) relay.
With the Headlamp Switch in the HEAD position and the Multifunction Switch (headlamp dimmer) in LO beam, use the J 39200 DMM to backprobe for continuity to ground from terminal 5 at the DRL Relay connector. Refer to Circuit Testing in Wiring Systems.

Is continuity present?

Go to Step 11

Go to Step 12

Replace the DRL Relay.

Is the repair complete?

Go to Step 13

Locate and repair the open or high resistance in CKT 525 (YEL) between S202 and the DRL (ZR2) Relay. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to Step 13

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3