Volt

Sidelight, Number Plate, and/or Tail Lamps Malfunction

When the indicator/multifunction switch is placed in the HEADLAMP or SIDELIGHT position, ground is applied to the sidelights ON signal circuit to the body control module (BCM). The BCM responds by applying voltage to the sidelights, tail lamps, and number plate lamps control circuits illuminating the sidelight, tail, and number plate lamps.

Schematic Reference

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

1. Vehicle in Service Mode, observe the scan tool Sidelights Switch parameter while turning the indicator/multifunction switch between the OFF and SIDELIGHT positions. The parameter should change between Active and Inactive.

⇒	If the parameter does not change between the commanded states, refer to Sidelight Switch Malfunction.

2. Command the Left Front Sidelight ON and OFF with a scan tool. The left front sidelight should turn ON and OFF when changing between the commanded states.

⇒	If the left front sidelight does not turn ON and OFF when commanded, refer to Sidelights Malfunction.

3. Command the Left Rear Sidelight ON and OFF with a scan tool. The left rear sidelight should turn ON and OFF when changing between the commanded states.

⇒	If the left rear sidelight does not turn ON and OFF when commanded, refer to Sidelights Malfunction.

4. Command the Right Front Sidelight ON and OFF with a scan tool. The right front sidelight should turn ON and OFF when changing between the commanded states.

⇒	If the right front sidelight does not turn ON and OFF when commanded, refer to Sidelights Malfunction.

5. Command the Right Rear Sidelight ON and OFF with a scan tool. The right rear sidelight should turn ON and OFF when changing between the commanded states.

⇒	If the right rear sidelight does not turn ON and OFF when commanded, refer to Sidelights Malfunction.

6. Command the Number Plate Lamps ON and OFF with a scan tool. The number plate lamps should turn ON and OFF when changing between the commanded states.

⇒	If the number plate lamps do not turn ON and OFF when commanded, refer to Number Plate Lamps Malfunction.

Sidelight Switch Malfunction

1. Vehicle OFF, disconnect the harness connector at the S78 Indicator/Multifunction Switch.
2. Vehicle OFF, all doors closed, all accessories OFF, and wait 2 minutes. Test for less than 10 Ω between the ground circuit terminal 6 and ground.

⇒	If greater then the specified range, test the ground circuit for an open/high resistance.

3. Vehicle in Service Mode, verify the scan tool Sidelights Switch parameter is Inactive.

⇒	If not the specified value, test the signal circuit terminal 7 for a short to ground. If the circuit tests normal, replace the K9 Body Control Module.

4. Install a 3 A fused jumper wire between the signal circuit terminal 7 and ground. Verify the scan tool Sidelights Switch parameter is Active.

⇒	If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module.

5. If all circuits test normal, replace the S78 Indicator/Multifunction Switch.

Sidelights Malfunction

1. Vehicle OFF, disconnect the harness connector at the inoperative sidelight.
2. Vehicle OFF, exterior lamps OFF, test for less than 5 Ω between the appropriate ground circuit terminal listed below and ground:

•	E4N Sidelight/Indicator Lamp - Left - terminal 1

•	E4P Sidelight/Indicator Lamp - Right - terminal 1

•	E42L Tail Lamp Assembly - Left - terminal 4

•	E42R Tail Lamp Assembly - Right - terminal 4

⇒	If greater than the specified range, test the ground circuit for an open/high resistance.

3. Connect a test lamp between the appropriate control circuit terminal listed below and ground:

•	E4N Sidelight/Indicator Lamp - Left - terminal 2

•	E4P Sidelight/Indicator Lamp - Right - terminal 2

•	E42L Tail Lamp Assembly - Left - terminal 2

•	E42R Tail Lamp Assembly - Right - terminal 2

4. Vehicle in Service Mode, command the appropriate Sidelight ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

⇒	If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K9 Body Control Module.

⇒	If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module.

5. If all circuits test normal, replace the inoperative park lamp.

Number Plate Lamps Malfunction

1. Vehicle OFF, disconnect the harness connector at the E7L Number Plate Lamp - Left and E7R Number Plate Lamp - Right.
2. Vehicle OFF, exterior lamps OFF, test for less than 5 Ω between each ground circuit terminal 2 and ground.

⇒	If greater than the specified range, test the ground circuit for an open/high resistance.

3. Connect a test lamp between the E7L Number Plate Lamp - Left control circuit terminal 1 and ground.
4. Vehicle in Service Mode, command the Number Plate Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

⇒	If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K9 Body Control Module.

⇒	If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module.

5. Vehicle OFF, connect a test lamp between the E7R Number Plate Lamp - Right control circuit terminal 1 and ground.
6. Vehicle in Service Mode, command the Number Plate Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

⇒	If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module.

7. If all circuits test normal, replace the inoperative number plate lamp bulb.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.