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 4

Go to Step 5

Place the headlamp dimmer switch in the HIGH BEAM position.

Are the high beam headlamps also inoperative?

Go to Step 7

Go to Step 13

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 6

Go to Step 28

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 26

Go to Step 29

1. Place the headlamp dimmer switch in the LOW BEAM position.
2. With a scan tool, observe the Head Lamp Switch parameter in the Instrument Cluster (IPC) inputs data list.

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

Go to Step 8

Go to Step 14

With the scan tool, command the HEADLAMP relay ON and OFF.

Do hear a click when you command the HEADLAMP relay ON and OFF?

Go to Step 11

Go to Step 9

1. Turn OFF the ignition.
2. Remove the HEADLAMP relay.
3. Turn ON the ignition with the engine OFF.

Connect a test lamp between the supply voltage circuit of the HEADLAMP relay coil and a good ground.

Does the test lamp illuminate?

Go to Step 10

Go to Step 21

1. Connect a test lamp between the supply voltage circuit and the control circuit of the HEADLAMP relay.
2. With a scan tool, command the HEADLAMP relay ON.

Does the test lamp illuminate?

Go to Step 24

Go to Step 16

1. Turn OFF the ignition.
2. Disconnect the HEADLAMP relay.
3. Turn ON the ignition, with the engine OFF.
4. Connect a test lamp between the battery positive voltage circuit of the HEADLAMP relay switch and a good ground.

Does the test lamp illuminate?

Go to Step 12

Go to Step 17

Connect a 20 amp fused jumper between the battery positive voltage circuit of the HEADLAMP relay switch and the headlamp supply voltage circuit.

Do the low beam headlamps illuminate?

Go to Step 24

Go to Step 18

1. Place the headlamp dimmer switch in the LOW BEAM position.
2. Disconnect the HIGH/LOW BEAM HEADLAMP relay.
3. Connect a 20 amp fused jumper between the headlamp supply voltage circuit of the HIGH/LOW BEAM HEADLAMP relay switch and the supply voltage circuit of the low beam headlamps.

Do the low beam headlamps illuminate?

Go to Step 25

Go to Step 28

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

Did you find and correct the condition?

Go to Step 35

Go to Step 15

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 35

Go to Step 23

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

Did you find and correct the condition?

Go to Step 35

Go to Step 27

Test for an open or short to ground in the battery positive voltage circuit of the HEADLAMP relay switch. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 35

Go to Step 19

Test for an open or high resistance in the headlamp supply voltage circuit of the HIGH/LOW BEAM HEADLAMP relay switch. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 35

Go to Step 22

Test for a short to ground in the headlamp supply voltage circuit of the HIGH/LOW BEAM HEADLAMP relay switch. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 35

Go to Step 20

Test for a short to ground in the supply voltage circuit of the high beam headlamps. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 35

Go to Step 28

Test for an open or high resistance in the supply voltage circuit of the HEADLAMP relay coil. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 35

Go to Step 27

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

Did you find and correct the condition?

Go to Step 35

Go to Step 25

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 35

Go to Step 30

Inspect for poor connections at the 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 35

Go to Step 31

Inspect for poor connections at the HIGH/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 35

Go to Step 32

Inspect for poor connections at the harness connector of 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 35

Go to Step 33

Inspect for poor connections at the harness connector of the Body Control Module (BCM). 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 35

Go to Step 34

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 35

--

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 35

--

Replace the headlamp switch. Refer to Headlamp Switch Replacement .

Did you complete the replacement?

Go to Step 35

--

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

Did you complete the replacement?

Go to Step 35

--

Replace the HIGH/LOW BEAM HEADLAMP relay. Refer to Relay Replacement in Wiring Systems.

Did you complete the replacement?

Go to Step 35

--

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

Did you complete the replacement?

Go to Step 35

--

Replace the Body Control Module (BCM). Refer to Body Control Module Replacement in Body Control System.

Did you complete the replacement?

Go to Step 35

--

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2