Volt

Indicator Lamps and/or Indicators Malfunction

Ground is applied at all times to the indicator/multifunction switch. The indicator lamps may only be activated with the vehicle mode switch in the SERVICE MODE or ON positions. When the indicator/multifunction switch is placed in either the TURN RIGHT or TURN LEFT position, ground is applied to the body control module (BCM) through either the right turn or left indicator switch signal circuit. The BCM responds to the indicator switch input by applying a pulsating voltage to the front and rear indicator lamps through there respective control circuits. When a indicator request is received by the BCM, a serial data message is sent to the instrument panel cluster requesting the respective indicator indicator be pulsed ON and OFF.

The tail lamp outage detection circuits are low current B+ circuits that will not illuminate a test lamp.

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 Right Indicator Switch and Left Indicator Switch parameters while cycling the indicator/multifunction switch between the right and left positions. The readings should change between Active and Inactive.

⇒	If the parameters do not change between the selected states, refer to Indicator/Multifunction Switch Malfunction.

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

⇒	If the left front indicator does not turn ON and OFF when changing between the commanded states, refer to Indicator Lamps Malfunction.

3. Command the Right Front Indicator Lamp ON and OFF with a scan tool. The right front indicator should turn ON and OFF when changing between the commanded states.

⇒	If the right front indicator does not turn ON and OFF when changing between the commanded states, refer to Indicator Lamps Malfunction.

4. Command the Left Rear Indicator/Brake Lamp ON and OFF with a scan tool. The left rear indicator should turn ON and OFF when changing between the commanded states.

⇒	If the left rear indicator does not turn ON and OFF when changing between the commanded states, refer to Indicator Lamps Malfunction.

5. Command the Right Rear Indicator/Brake Lamp ON and OFF with a scan tool. The right rear indicator should turn ON and OFF when changing between the commanded states.

⇒	If the right rear indicator does not turn ON and OFF when changing between the commanded states, refer to Indicator Lamps Malfunction.

6. Observe the left and right indicator lamps and indicator indicators on the instrument panel cluster while activating the left and right indicators. The left and right indicator lamps and indicators should illuminate and flash at a normal rate when turned ON.

⇒	If the left and right indicator lamps and indicators illuminate but flash in a rapid manner, refer to Tail Lamp Outage Detection Malfunction.

7. Command the Instrument Cluster Gauge Sweep Test ON and OFF with a scan tool. The left and right indicator indicators should turn ON and OFF when changing between the commanded states.

⇒	If the left and right indicator indicators do not turn ON and OFF when commanded, refer to Indicator Indicators Malfunction.

Indicator/Multifunction Switch Malfunction

1. Vehicle OFF, disconnect the harness connector at the S78 Indicator/Multifunction Switch.
2. Vehicle OFF, scan tool disconnected, 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 than the specified range, test the ground circuit for an open/high resistance.

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

⇒	If not the specified value, test the signal circuit terminal 4 for a short to ground. If the circuit tests normal, replace the K9 Body Control Module.

4. Verify the scan tool Right Indicator Switch parameter is Inactive.

⇒	If not the specified value, test the signal circuit terminal 5 for a short to ground. If the circuit tests normal, replace the K9 Body Control Module.

5. Install a 3 A fused jumper wire between the signal circuit terminal 4 and ground. Verify the scan tool Left Indicator 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.

6. Install a 3 A fused jumper wire between the signal circuit terminal 5 and ground. Verify the scan tool Right Indicator 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.

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

Indicator Lamps Malfunction

1. Vehicle OFF, disconnect the harness connector at the inoperative indicator lamp.
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

•	E4Y Indicator Repeater Lamp - Left - terminal C

•	E4P Sidelight/Indicator Lamp - Right - terminal 1

•	E4Z Indicator Repeater Lamp - Right - terminal C

•	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 3

•	E4Y Indicator Repeater Lamp - Left - terminal A

•	E4P Sidelight/Indicator Lamp - Right - terminal 3

•	E4Z Indicator Repeater Lamp - Right - terminal D

•	E42L Tail Lamp Assembly - Left - terminal 1

•	E42R Tail Lamp Assembly - Right - terminal 1

4. Vehicle in Service Mode, command the appropriate Indicator Lamp 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 indicator lamp.

Tail Lamp Outage Detection Malfunction

1. Vehicle OFF, disconnect the harness connector at the inoperative tail lamp assembly.
2. Vehicle in Service Mode, test for B+ between the signal circuit terminal 3 and ground.

⇒	If less than the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module.

3. Verify that a test lamp does not illuminate between the signal circuit terminal 3 and ground.

⇒	If the test lamp illuminates, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K9 Body Control Module.

4. If all circuits test normal, replace the inoperative tail lamp assembly.

Indicator Indicators Malfunction

Vehicle in Service Mode, with a scan tool perform the Instrument Cluster Gauge Sweep Test and observe the left and right indicator indicators.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.