Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Hazard Switch Signal | 2 | 2 | 2 | -- |
Left Tail Lamp Outage Detection Signal | 4 | 4 | 4 | -- |
Left Turn Signal Switch Signal | 3 | 3 | 3 | -- |
Right Tail Lamp Outage Detection Signal | 4 | 4 | 4 | -- |
Right Turn Signal Switch Signal | 3 | 3 | 3 | -- |
Left Front Turn Signal Lamp Control | 1 | 1 | 1 | -- |
Right Front Turn Signal Lamp Control | 1 | 1 | 1 | -- |
Left Rear Stop/Turn Lamp Control | 1 | 1 | 1 | -- |
Right Rear Stop/Turn Lamp Control | 1 | 1 | 1 | -- |
Hazard Switch Ground | -- | 2 | -- | -- |
Left Rear Stop/Turn Lamp Ground | -- | 1 | -- | -- |
Left Repeater Lamp Ground | -- | 1 | -- | -- |
Right Repeater Lamp Ground | -- | 1 | -- | -- |
Right Rear Stop/Turn Lamp Ground | -- | 1 | -- | -- |
Turn Signal/Multifunction Switch Ground | -- | 3 | -- | -- |
Turn Signal Lamp - LF Ground | -- | 1 | -- | -- |
Turn Signal Lamp - RF Ground | -- | 1 | -- | -- |
1. Turn Signal Lamps and/or Indicators Malfunction 2. Hazard Lamps Malfunction 3. Turn Signal Switch Malfunction 4. Tail Lamp Outage Detection Malfunction | ||||
Circuit/System Description
With the ignition switch in the RUN position, the turn signal lamps will illuminate when the driver places the turn signal switch in the right or left positions. The instrument panel module (IPM) monitors the signal circuit of the turn signal/multifunction switch. The IPM relays the turn signal switch status to the rear integration module (RIM) via serial data. The RIM uses the status of the turn signal switch to command the turn signals ON and OFF. The RIM controls both front and rear turn signals. The IPM also sends a serial data message to the instrument panel cluster (IPC) to enable the turn signal indicators located in the IPC ON and OFF depending on the position of the turn signal switch. Voltage is supplied to the front and rear turn signals by the RIM. Ground is provided to the front turn signals at G104. The rear turn signals are grounded at G401 and G402. The turn signal/multifunction switch is grounded at G200.
Diagnostic Aids
The tail lamp outage detection circuits are low current B+ circuits supplied by the BCM. For purposes of testing, a test lamp connected between the outage detection circuit and ground will not illuminate due to the low current.
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Exterior Lighting Systems Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Ignition ON, observe the scan tool Right and Left Turn/Hazard Lamp Command parameters while cycling the turn signal switch between the left and right positions. The parameters should change between On and Off.
- Ignition ON, observe the left turn signal lamps and turn signal indicators on the IPC while activating the left turn signals. The left turn signal lamps and indicators should illuminate and flash when turned ON.
- Ignition ON, observe the right turn signal lamps and turn signal indicators on the IPC while activating the right turn signals. The right turn signal lamps and indicators should illuminate and flash when turned ON.
| ⇒ | If the parameters do not change between the commanded states, refer to Turn Signal Switch Malfunction. |
| ⇒ | If the parameters change between the commanded states and the turn signal indicators are inoperative, refer to Turn Signal Indicators Malfunction. |
| ⇒ | If the left turn signal lamps and indictors illuminate but flash in a rapid manner, refer to Tail Lamp Outage Detection Malfunction. |
| ⇒ | If the left turn signal lamps and indictors illuminate but flash in a rapid manner, refer to Tail Lamp Outage Detection Malfunction. |
Circuit/System Testing
Turn Signal Switch Malfunction
- Ignition OFF, disconnect the X1 harness connector at the turn signal/multifunction switch.
- Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal G.
- Ignition ON, verify the scan tool Left Front Turn/Hazard Command parameter is Off.
- Verify the scan tool Right Front Turn/Hazard Command parameter is Off.
- Install a 3A fused jumper wire between the signal circuit terminal F and ground. Verify the scan tool Left Front Turn/Hazard Command parameter is On.
- Install a 3A fused jumper wire between the signal circuit terminal H and ground. Verify the scan tool Right Front Turn/Hazard Command parameter is On.
- If all circuits test normal, test or replace the turn signal/multifunction switch.
| ⇒ | If the test lamp does not illuminate, test the ground circuit for an open/high resistance. |
| ⇒ | If not the specified value, test the signal circuit terminal F for a short to ground. If the circuit tests normal, replace the IPM. |
| ⇒ | If not the specified value, test the signal circuit terminal H for a short to ground. If the circuit tests normal, replace the IPM. |
| ⇒ | 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 IPM. |
| ⇒ | 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 IPM. |
Turn Signal Lamps Malfunction
- Ignition OFF, disconnect the harness connector at the inoperative turn signal/repeater lamp.
- Ignition OFF, exterior lamps OFF, test for less than 5 ohms between the ground circuit and ground.
- Connect a test lamp between the control circuit and the ground circuit.
- Command the appropriate turn signal lamp ON and OFF with the turn signal/multifunction switch. The test lamp should turn ON and OFF when changing between the commanded states.
- If all circuits test normal, test or replace the appropriate turn signal lamp assembly.
| ⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
| ⇒ | If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the RIM. |
| ⇒ | 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 RIM. |
Tail Lamp Outage Detection Malfunction
- Ignition OFF, disconnect the harness connector at the appropriate rear tail lamp assembly.
- Ignition ON, test for B+ between the outage detection circuit terminal C and ground.
- Ignition ON, connect a test lamp between the outage detection circuit terminal C and ground. The test lamp should not Illuminate.
- If all circuits test normal, test or replace the tail lamp assembly.
| ⇒ | If the measured voltage is less than B+, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the RIM. |
| ⇒ | If the test lamp illuminates, test the signal circuit for a short to voltage. If the circuit tests normal, replace the RIM. |
Turn Signal Indicators Malfunction
Ignition ON, with a scan tool perform the Display Test for the instrument panel cluster (IPC) and observe the turn signal lamp indicators.
| ⇒ | If the turn signal lamp indicators illuminate during the test, replace the IPM. |
| ⇒ | If the turn signal lamp indicators do not illuminate during the test or remain illuminated at all times, replace the IPC. |
Component Testing
Tail Lamp Assembly
- Ignition OFF, disconnect the harness connector at the appropriate rear tail lamp assembly.
- Test for infinite resistance between the outage detection terminal C and the ground terminal D at the tail lamp assembly.
| ⇒ | If not the specified value, replace the tail lamp assembly. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for IPC or IPM replacement, setup, and programming |
