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. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. Place the headlamp switch in the OFF position.
4. Place the headlamp dimmer switch in the LOW BEAM position.
5. Place the twilight delay switch in the OFF position.
6. 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 OFF?

Go to Step 3

Go to Step 10

With a scan tool, observe the Low Beam Output parameter.

Does the scan tool indicate that the Low Beam Output parameter is OFF?

Go to Step 4

Go to Step 20

Are the high beam headlamps on?

Go to Step 5

Go to Step 6

With the scan tool, observe the Flash to Pass Switch input parameter.

Does the scan tool indicate that the Flash to Pass Switch parameter is OFF?

Go to Step 8

Go to Step 11

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

Did the low beam headlamps turn OFF?

Go to Step 7

Go to Step 21

1. Turn On the ignition, with the engine OFF.
2. Connect a test lamp between the supply voltage circuit of the HDLP LO BM relay coil and the control circuit of the HDLP LO BM relay.
3. Turn ON the ignition, with the engine OFF.

Did the test lamp illuminate?

Go to Step 12

Go to Step 18

1. Turn OFF the ignition.
2. Disconnect the HDLP HI BM relay.
3. Turn ON the ignition, with the engine OFF.

Did the high beam headlamps turn OFF?

Go to Step 9

Go to Step 22

1. Turn On the ignition, with the engine OFF.
2. Connect a test lamp between the supply voltage circuit of the HDLP HI BM relay coil and the control circuit of the HDLP HI BM relay.
3. Turn ON the ignition, with the engine OFF.

Did the test lamp illuminate?

Go to Step 13

Go to Step 19

1. Turn OFF the ignition.
2. Disconnect the headlamp switch.
3. Turn ON the ignition, with the engine OFF.
4. With a scan tool observe the Headlamp Switch parameter in the DIM inputs data list.

Does the scan tool indicate that the Headlamp Switch is OFF?

Go to Step 17

Go to Step 15

1. Disconnect the headlamp dimmer switch.
2. With a scan tool observe the Flash to Pass Switch parameter in the DIM inputs data list.

Does the scan tool indicate that the Flash to Pass Switch parameter is OFF?

Go to Step 16

Go to Step 14

Test for a short to ground in the headlamp low beam relay control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 28

Go to Step 20

Test for a short to ground in the headlamp high beam relay control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 28

Go to Step 20

Test for a short to ground in the flash to pass switch signal circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 28

Go to Step 20

Test for a short to ground in the headlamps on signal circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 28

Go to Step 20

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 28

Go to Step 23

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 28

Go to Step 24

Inspect for poor connections at the harness connector of 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 28

Go to Step 25

Inspect for poor connections at the harness connector of the HDLP HI 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 28

Go to Step 26

Inspect for poor connections at the harness connector of 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 28

Go to Step 27

Repair the short to voltage in the headlamp low beam supply voltage circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 28

--

Repair the short to voltage in the headlamp high beam supply voltage circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 28

--

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 28

--

Replace the headlamp switch assembly. Refer to Headlamp Switch Replacement .

Did you complete the replacement?

Go to Step 28

--

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

Did you complete the replacement?

Go to Step 28

--

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

Did you complete the replacement?

Go to Step 28

--

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 28

--

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2

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 ignition, with the engine OFF.
2. Place the headlamp switch in the OFF position.
3. Place the headlamp dimmer switch in the LOW BEAM position.
4. Place the twilight delay switch in the OFF position (LHD).

Do either the low beam headlamps or the high beam headlamps remain illuminated?

Go to Step 3

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

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 OFF?

Go to Step 4

Go to Step 12

Are the high beam headlamps on?

Go to Step 5

Go to Step 6

With the scan tool, observe the Flash to Pass Switch input parameter.

Does the scan tool indicate that the Flash to Pass Switch parameter is OFF?

Go to Step 10

Go to Step 13

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

Did the low beam headlamps turn OFF?

Go to Step 9

Go to Step 7

1. Turn OFF the ignition.
2. Disconnect the DRL relay.
3. Turn ON the ignition, with the engine OFF.

Did the low beam headlamps turn OFF?

Go to Step 8

Go to Step 19

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

Does the test lamp illuminate?

Go to Step 18

Go to Step 25

1. Turn On the ignition, with the engine OFF.
2. Connect a test lamp between the supply voltage circuit of the HDLP LO BM relay coil and the control circuit of the HDLP LO BM relay.
3. Turn ON the ignition, with the engine OFF.

Did the test lamp illuminate?

Go to Step 14

Go to Step 22

1. Turn OFF the ignition.
2. Disconnect the HDLP HI BM relay.
3. Turn ON the ignition, with the engine OFF.

Did the high beam headlamps turn OFF?

Go to Step 11

Go to Step 26

Connect a test lamp between the supply voltage circuit of the HDLP HI BM relay coil and the control circuit of the HDLP HI BM relay.

Did the test lamp illuminate?

Go to Step 15

Go to Step 23

1. Turn OFF the ignition.
2. Disconnect the headlamp switch.
3. Turn ON the ignition, with the engine OFF.
4. With a scan tool observe the Head lamp Switch parameter in the DIM inputs data list.

Does the scan tool indicate that the Headlamp Switch parameter is OFF?

Go to Step 21

Go to Step 17

1. Disconnect the headlamp dimmer switch.
2. With a scan tool observe the Flash to Pass Switch parameter in the DIM inputs data list.

Does the scan tool indicate that the Flash to Pass Switch parameter is OFF?

Go to Step 20

Go to Step 16

Test for a short to ground in the headlamp low beam relay control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 34

Go to Step 24

Test for a short to ground in the headlamp high beam relay control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 34

Go to Step 24

Test for a short to ground in the flash to pass switch signal circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 34

Go to Step 24

Test for a short to ground in the headlamps on signal circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 34

Go to Step 24

Test for a short to ground in the DRL relay control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 34

Go to Step 24

Test for a short to battery positive voltage in the headlamp low beam supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 34

Go to Step 27

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 34

Go to Step 28

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 34

Go to Step 29

Inspect for poor connections at the harness connector of 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 34

Go to Step 30

Inspect for poor connections at the harness connector of the HDLP HI 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 34

Go to Step 31

Inspect for poor connections at the harness connector of 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 34

Go to Step 32

Inspect for poor connections at the harness connector of 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 34

Go to Step 33

Repair the short to battery positive voltage in the headlamp high beam supply voltage circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 34

--

Repair the short to battery positive voltage in the DRL headlamp supply voltage circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 34

--

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

Did you complete the replacement?

Go to Step 34

--

Replace the headlamp switch assembly. Refer to Headlamp Switch Replacement , or Turn Signal Multifunction Switch Replacement in Steering Wheel and Column (RHD).

Did you complete the replacement?

Go to Step 34

--

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

Did you complete the replacement?

Go to Step 34

--

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

Did you complete the replacement?

Go to Step 34

--

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 34

--

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

Did you complete the replacement?

Go to Step 34

--

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2