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

1

Did you perform the Lighting Systems Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

1. Turn ON the ignition with the engine OFF.
2. Place the headlamp switch in the HEADLAMP position.
3. Place the headlamp dimmer switch in the LOW BEAM position.

Do the low beam headlamps illuminate?

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

Go to Step 3

Are both low beam headlamps inoperative?

Go to Step 6

Go to Step 4

1. Disconnect the inoperative headlamp.
2. Connect a test lamp between the supply voltage circuit of the inoperative headlamp and a good ground.

Does the test lamp illuminate?

Go to Step 5

Go to Step 22

Connect a test lamp between the supply voltage circuit of the inoperative low beam headlamp and the ground circuit of the inoperative low beam headlamp.

Does the test lamp illuminate?

Go to Step 20

Go to Step 24

1. Turn ON the ignition, with the engine OFF.
2. With a scan tool, observe the Head Lamp Switch parameter in the Dash Integration Module (DIM) Inputs Data List.

Does the scan tool indicate that the Head Lamp Switch parameter is ON?

Go to Step 7

Go to Step 13

1. Place the headlamp switch in the OFF position.
2. With a scan tool, select from the Dash Integration Module (DIM) Special Functions Output Controls, the Low/High Beam Relay.
3. With the scan tool, command the HDLP LO BM relay ON and OFF.

Do hear a click when you command the HDLP LO BM relay ON and OFF?

Go to Step 11

Go to Step 8

1. Turn OFF the ignition.
2. Remove the HDLP LO BM relay.
3. Turn ON the ignition with the engine OFF.

Connect a test lamp between the controlled positive voltage circuit of the HDLP LO BM relay coil and a good ground.

Does the test lamp illuminate?

Go to Step 9

Go to Step 25

1. Connect a test lamp between the controlled positive voltage circuit and the control circuit of the HDLP LO BM relay coil.
2. With a scan tool, command the HDLP LO BM relay ON and OFF.

Does the test lamp turn ON and OFF with each command?

Go to Step 18

Go to Step 10

1. Disconnect the headlamp dimmer switch.
2. Connect a fused jumper between the control circuit of the HDLP LO BM relay and the headlamp control circuit.
3. With a scan tool, command the HDLP LO BM relay ON and OFF.

Does the test lamp turn ON and OFF with each command?

Go to Step 19

Go to Step 15

1. Turn OFF the ignition.
2. Remove the HDLP LO BM relay.
3. Connect a test lamp between the battery positive voltage circuit of the HDLP LO BM relay switch and a good ground.

Does the test lamp illuminate?

Go to Step 12

Go to Step 23

Connect a 10 amp fused jumper between the battery positive voltage circuit of the HDLP LO BM relay switch and the supply voltage circuit of the low beam headlamps.

Do the low beam headlamps illuminate?

Go to Step 18

Go to Step 24

Test for an open or high resistance in the headlamps on signal circuit of the headlamp switch. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 31

Go to Step 14

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

Did you find and correct the condition?

Go to Step 31

Go to Step 17

Test for an open or short to battery positive voltage in the control circuit of the HDLP LO BM relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 31

Go to Step 16

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

Did you find and correct the condition?

Go to Step 31

Go to Step 21

Inspect for poor connections at 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 31

Go to Step 26

Inspect for poor connections at the HDLP LO BM 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 31

Go to Step 28

Inspect for poor connections at 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 31

Go to Step 27

Inspect for poor connections at the inoperative low beam headlamp. 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 31

Go to Step 29

Inspect for poor connections at the Dash Integration Module (DIM). 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 31

Go to Step 30

Repair an open or short to ground in the supply voltage circuit of the low beam headlamps. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 31

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Repair an open or high resistance in the battery positive voltage circuit of the HDLP LO BM relay switch. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 31

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Repair an open or high resistance in the ground circuit of the low beam headlamps. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 31

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Repair an open or high resistance in the controlled positive voltage circuit of the HDLP LO BM relay coil. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 31

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Replace the headlamp switch. Refer to Headlamp Switch Replacement .

Did you complete the replacement?

Go to Step 31

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Replace the headlamp dimmer switch. Refer to Turn Signal Multifunction Switch Replacement in Steering Wheel and Column.

Did you complete the replacement?

Go to Step 31

--

Replace the HDLP LO BM relay. Refer to Relay Replacement in Wiring Systems.

Did you complete the replacement?

Go to Step 31

--

Replace the inoperative low beam headlamp. Refer to Headlamp Bulb Replacement .

Did you complete the replacement?

Go to Step 31

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Important:: Perform the setup procedure for the Dash Integration Module (DIM). Refer to Body Control Module (BCM) Programming/RPO Configuration .

Replace the DIM. Refer to Dash Integration Module Replacement in Body Control System.

Did you complete the replacement?

Go to Step 31

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Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2