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

Connector End View Reference: Master Electrical Component List in Wiring Systems

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 low beam position.
3. Turn OFF the headlamps.

Do the low beam headlamps operate properly?

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

Go to Step 3

1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. Turn ON the headlamps.
4. With the scan tool, observe the Headlamp Switch Input parameter in the dash integration module (DIM) Inputs data list.

Does the data parameter display ON?

Go to Step 4

Go to Step 5

With a scan tool, command the headlamp low beam relay ON and OFF from the DIM Output Control data list.

Did both of the low beam headlamps turn ON and OFF?

Go to Step 18

Go to Step 6

1. Turn OFF the ignition.
2. Disconnect the headlamp switch.
3. Connect a 3-amp fused jumper between the headlamp switch headlamps ON signal circuit of the headlamp switch and the ground circuit of the headlamp switch.
4. Turn ON the ignition, with the engine OFF.

Does the Headlamp Switch Input data parameter display ON?

Go to Step 16

Go to Step 14

1. Turn OFF the ignition.
2. Disconnect the HDLP LO BM relay. Refer to Relay Replacement in Wiring Systems.
3. Connect a test lamp between the control side supply voltage circuit of the HDLP LO BM relay and a good ground.
4. Turn ON the headlamps.
5. Turn ON the ignition, with the engine OFF.

Does the test lamp illuminate?

Go to Step 7

Go to Step 12

Connect a test lamp between the switch side supply voltage circuit of the HDLP LO BM relay and ground.

Does the test lamp illuminate?

Go to Step 8

Go to Step 21

1. Turn OFF the ignition.
2. Connect a test lamp between the headlamp low beam relay control circuit of the HDLP LO BM relay and the control side supply voltage circuit of the HDLP LO BM relay.
3. Turn ON the ignition, with the engine OFF.
4. With a scan tool command the headlamp low beam relay ON and OFF.

Did the test lamp turn ON and OFF?

Go to Step 9

Go to Step 13

1. Turn OFF the ignition.
2. Connect a 20-amp fused jumper between the switch side supply voltage circuit of the HDLP LO BM relay and the headlamp low beam supply voltage circuit of the HDLP LO BM relay.
3. Turn ON the ignition, with the engine OFF.

Did both of the low beam headlamps illuminate?

Go to Step 17

Go to Step 10

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

Does the test lamp illuminate?

Go to Step 19

Go to Step 11

Test the headlamp low beam supply voltage circuit for an open, high resistance 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 26

Go to Step 20

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

Did you complete the repair?

Go to Step 26

Go to Step 18

Test the control circuit of the low beam headlamp relay for a short to battery positive voltage or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 26

Go to Step 18

Test the ground circuit of the headlamp switch 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 26

Go to Step 15

Test the headlamp switch on signal circuit of the headlamp switch 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 26

Go to Step 18

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 26

Go to Step 22

Inspect for poor connections at the low beam headlamp 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 26

Go to Step 23

Inspect for poor connections at the harness connector of the 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 26

Go to Step 24

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 26

Go to Step 25

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

Did you complete the repair?

Go to Step 26

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Repair the high resistance or open in the switch side supply voltage circuit of the low beam headlamp relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 26

--

Replace the headlamp switch. Refer to Headlamp Switch Replacement .

Did you complete the replacement?

Go to Step 26

--

Replace the low beam headlamp relay. Refer to Relay Replacement in Wiring Systems.

Did you complete the replacement?

Go to Step 26

--

Important:: After replacement perform the setup procedure for the DIM. Refer to Body Control Module (BCM) Programming/RPO Configuration in Body Control System.

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

Did you complete the replacement?

Go to Step 26

--

Replace the inoperative headlamp bulb. Refer to Headlamp Replacement .

Did you complete the replacement?

Go to Step 26

--

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2