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

Did you review the daytime running lights (DRL) description and operation and perform the necessary inspections?

Go to Step 2

Go to Symptoms - Lighting Systems

1. Disengage the parking brake.
2. Place the headlamp switch in the OFF position.
3. Turn ON the ignition, with the engine OFF.

Do the DRLs illuminate?

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

Go to Step 3

Is the park brake indicator illuminated?

Go to Park Brake Indicator Always On in Park Brake

Go to Step 4

1. Turn OFF the ignition.
2. Disconnect the DRL relay.
3. Probe the DRL diode supply voltage circuit of the DRL relay with a test lamp that is connected to a good ground.
4. Turn ON the ignition, with the engine OFF.

Does the test lamp illuminate?

Go to Step 5

Go to Step 8

1. Turn OFF the ignition.
2. Connect a 30 amp fused jumper wire between the DRL diode supply voltage circuit of the DRL relay and the headlamp low beam supply voltage circuit of the DRL relay.
3. Turn ON the ignition, with the engine OFF.

Do the DRLs illuminate?

Go to Step 6

Go to Step 13

Probe the ignition positive voltage circuit of the DRL relay with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 7

Go to Step 14

Connect a test lamp between the ignition positive voltage circuit of the DRL relay and the DRL relay control circuit.

Does the test lamp illuminate?

Go to Step 10

Go to Step 9

Test the DRL diode supply voltage circuit of the DRL relay for an open, high resistance, or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 18

Go to Step 11

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

Did you find and correct the condition?

Go to Step 18

Go to Step 12

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 18

Go to Step 15

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 18

Go to Step 16

Inspect for poor connections at the harness connector of the DRL control module. 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 18

Go to Step 17

Repair an open, high resistance, or short to ground in the headlamp low beam supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 18

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Repair an open, high resistance, or short to ground in the ignition positive voltage circuit of the DRL relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 18

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Replace the DRL relay. Refer to Daytime Running Lamps (DRL) Relay Replacement .

Did you complete the replacement?

Go to Step 18

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Replace the headlamp switch. Refer to Headlamp Switch Replacement .

Did you complete the replacement?

Go to Step 18

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

Did you complete the replacement?

Go to Step 18

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Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3