Schematic Reference: Headlights/Daytime Running Lights (DRL) Schematics

Did you review the Exterior Lighting System Description and Operation and perform the necessary inspections?

Go to Step 2

Go to Symptoms - Lighting Systems

1. Turn the ignition to the RUN position.
2. Turn the headlamp switch to the OFF position.

Are the headlamps illuminated?

Go to Step 3

Go to Step 4

Are the park lamps illuminated?

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

Go to Step 5

Place the headlamp switch in the HEAD position.

Do the headlamps operate from the headlamp switch?

Go to Step 6

Go to Headlamps Inoperative - Low Beams

Place the headlamp switch in the HEAD position.

Do the park lamps operate from the headlamp switch?

Go to Step 11

Go to Park Lamps Inoperative

1. Turn the ignition to the RUN position.
2. Turn the headlamp switch to the OFF position.
3. Remove the DRL relay.
4. Probe the exterior lamps OFF signal circuit of the daytime running lamps (DRL) relay connector with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 7

Go to Step 10

Connect a fused jumper between the exterior lamps OFF signal circuit and the headlamp supply voltage circuit of the daytime running lamps (DRL) relay connector.

Do the low beam headlamp illuminate?

Go to Step 8

Go to Step 14

Probe the ignition 3 voltage circuit of the daytime running lamps (DRL) relay connector with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 9

Go to Step 15

Probe the ground circuit of the daytime running lamps (DRL) relay connector with a test lamp that is connected to a battery voltage.

Does the test lamp illuminate?

Go to Step 13

Go to Step 16

Test for an open or high resistance in the exterior lamps OFF signal circuit of the daytime running lamps (DRL) relay. Refer to Testing for Intermittent Conditions and Poor Connections or to Circuit Testing in Wiring Systems.

Did you find and correct the condition?

Go to Step 19

Go to Step 12

Test for an open or high resistance in the ignition 3 voltage circuit of the headlamp switch. Refer to Testing for Intermittent Conditions and Poor Connections or to Circuit Testing in Wiring Systems.

Did you find and correct the condition?

Go to Step 19

Go to Step 12

Inspect for poor connections at the harness connector of 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 19

Go to Step 18

Inspect for poor connections at the harness connector of 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 19

Go to Step 17

Repair a poor connection or open in the supply voltage circuit of the low beam headlamps. Refer to Testing for Intermittent Conditions and Poor Connections or to Connector Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 19

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Repair a poor connection or open in the ignition 3 voltage circuit of the daytime running lamps (DRL) relay. Refer to Testing for Intermittent Conditions and Poor Connections or to Connector Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 19

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Repair a poor connection or open in the ground circuit of the daytime running lamps (DRL) relay. Refer to Testing for Intermittent Conditions and Poor Connections or to Connector Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 19

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

Did you complete the replacement?

Go to Step 19

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Replace the headlamp switch. Refer to Headlamp Switch Replacement .

Did you complete the replacement?

Go to Step 19

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Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2

Schematic Reference: Headlights/Daytime Running Lights (DRL) Schematics

Did you review the Exterior Lighting System Description and Operation and perform the necessary inspections?

Go to Step 2

Go to Symptoms - Lighting Systems

1. Place the ignition switch in the OFF position.
2. Engage the park brake.
3. Place the headlamp switch in the OFF position.
4. Turn ON the ignition, with the engine OFF.
5. Place the turn signal switch in the RH ON position.
6. Place the turn signal switch in the LH ON position.

Do the front turn signals operate properly?

Go to Step 3

Go to Turn Signal Lamps and/or Indicators Inoperative

IMPORTANT:  The domestic Pontiac does not have a DRL ambient light sensor. For domestic Pontiac, do not apply a bright light to the DRL ambient light sensor.

1. Release the park brake.
2. Apply a bright incandescent light to the DRL ambient light sensor.
3. Place the turn signal switch in the OFF position.

Do the front turn signals lamps illuminate?

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

Go to Step 4

Is the park brake indicator in the instrument panel cluster (IPC) ON?

Go to Brake Warning Indicator Always On in Hydraulic Brakes

Go to Step 5

Are the headlamps and park lamps illuminated?

Go to Step 6

Go to Step 8

Is the vehicle a domestic Pontiac?

Go to Step 11

Go to Step 7

1. Turn OFF the ignition.
2. Disconnect the DRL ambient light sensor.
3. Place a fused jumper across the DRL ambient light sensor connector.
4. Turn ON the ignition, with the engine OFF.

Do the turn signal lamps illuminate?

Go to Step 17

Go to Step 11

1. Turn OFF the ignition.
2. Disconnect the daytime running lamp (DRL) module connector.
3. Turn ON the ignition, with the engine OFF.
4. Probe the ignition 3 voltage circuit of the DRL module connector with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 9

Go to Step 14

Probe the ignition 1 voltage circuit of the DRL module connector with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 10

Go to Step 15

Probe the ground circuit of the DRL module connector with a test lamp that is connected to battery voltage.

Does the test lamp illuminate?

Go to Step 13

Go to Step 16

Test the low reference circuit of the DRL ambient light sensor for following:

Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 19

Go to Step 12

Test the signal circuit of the DRL ambient light sensor for following:

Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 19

Go to Step 18

Inspect for poor connections at the daytime running lamps DRL module. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 19

Go to Step 18

Repair the open or high resistance in the ignition 3 voltage circuit of the DRL module. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 19

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Repair the open or high resistance in the ignition 1 voltage circuit of the DRL module. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 19

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Repair the open or high resistance in the ground circuit of the DRL module. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 19

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Replace the DRL ambient light sensor. Refer to Daytime Running Lamp (DRL) Ambient Light Sensor Replacement .

Did you complete the replacement?

Go to Step 19

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Replace the DRL module. Refer to Daytime Running Lights (DRL) Control Module Replacement .

Did you complete the replacement?

Go to Step 19

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Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2