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

1

Did you perform the Lighting System Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

1. Turn ON the headlamps.
2. Position the headlamp dimmer switch in the high beam position.
3. Turn OFF the headlamps.

Do the high beam headlamps operate properly?

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

Go to Step 3

Do the low beam headlamps operate properly?

Go to Step 4

Go to Headlamps Inoperative - Low Beams

1. Disconnect the lamp control module (LCM).
2. Connect a 20-amp fused jumper between the headlamp high beam supply voltage circuit of the LCM and battery positive voltage.

Do both of the high beam headlamps illuminate?

Go to Step 5

Go to Step 6

1. Connect a test lamp between the headlamp dimmer switch high beam signal circuit of the LCM and battery positive voltage.
2. Operate the high beam switch ON and OFF.

Did the test lamp turn ON and OFF with the high beam switch?

Go to Step 15

Go to Step 7

1. Disconnect the inoperative high beam headlamp bulb.
2. Connect a test lamp between the inoperative headlamp bulb headlamp high beam supply voltage circuit and inoperative headlamp bulb ground circuit.

Does the test lamp illuminate?

Go to Step 14

Go to Step 9

Test the headlamp dimmer switch ground circuit for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 20

Go to Step 8

Test the headlamp dimmer switch high beam signal circuit of the LCM for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 20

Go to Step 13

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

Did you find and correct the condition?

Go to Step 20

Go to Step 10

Does the vehicle have RPO T62, daytime running - delete?

Go to Step 16

Go to Step 11

Is the left high beam headlamp inoperative?

Go to Step 12

Go to Step 16

Test the DRL headlamp high beam supply voltage circuit of the LCM for a high resistance, a open or a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 20

Go to Step 15

Inspect for poor connections at the harness connector of the headlamp dimmer 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 20

Go to Step 17

Inspect for poor connections at the inoperative headlamp bulb. 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 20

Go to Step 18

Inspect for poor connections at the harness connector of the LCM. 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 20

Go to Step 19

Repair the open or high resistance in the inoperative high beam headlamp ground circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 20

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Replace the headlamp dimmer switch. Refer to Multifunction, Turn Signal, and Hazard Switch Replacement - On Vehicle in Steering Wheel and Column.

Did you complete the replacement?

Go to Step 20

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Replace the inoperative headlamp bulb. Refer to Headlamp Bulb Replacement .

Did you complete the replacement?

Go to Step 20

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Replace the LCM. Refer to Lamp Control Module Replacement .

Did you complete the replacement?

Go to Step 20

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Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2