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 |
|---|---|---|---|---|
CTSY Fuse B+ | 1 | 1 | -- | -- |
LT STOP TRN Fuse B+ | 1 | 1 | -- | -- |
RT STOP TRN Fuse B+ | 1 | 1 | -- | -- |
Hazard Switch Signal | 2 | 2 | 2 | -- |
Left Turn Signal Switch Signal | 3 | 3 | 3 | -- |
Right Turn Signal Switch Signal | 3 | 3 | 3 | -- |
Left Front Turn Signal Lamp Control | 1 | 1 | 1 | -- |
Left Rear Turn Lamp Control | 1 | 1 | 1 | -- |
Right Rear Turn Lamp Control | 1 | 1 | 1 | -- |
Right Front Turn Signal Lamp Control | 1 | 1 | 1 | -- |
Hazard Switch Ground | -- | 2 | -- | -- |
Left Rear Turn Signal Lamp Ground | -- | 1 | -- | -- |
Left Front Park/Turn Signal Lamp Ground | -- | 1 | -- | -- |
Right Front Park/Turn Signal Lamp Ground | -- | 1 | -- | -- |
Right Rear Turn Signal Lamp Ground | -- | 1 | -- | -- |
Tail/Stop Lamp Ground | -- | 1 | -- | -- |
Turn Signal/Multifunction Switch Ground | -- | 3 | -- | -- |
1. Turn Signal Lamps and/or Indicators Malfunction 2. Hazard Lamps Malfunction 3. Turn Signal Switch Malfunction | ||||
Circuit/System Description
The hazard flashers may be activated in any power mode. The hazard switch is located on the turn signal/multifunction switch and is permanently grounded through G200. When the hazard switch is placed in the ON position, ground is applied through the hazard switch signal circuit to the body control module (BCM). The BCM supplies battery voltage to all four turn signal lamps in an ON and OFF duty cycle. When the hazard switch is activated, the BCM sends a GMLAN serial data message to the instrument panel cluster (IPC) requesting both turn signal indicators to be cycled ON and OFF.
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 Hazard Lamp Switch parameter while operating the hazard switch ON and OFF. The reading should change between Active and Inactive.
Circuit/System Testing
- Ignition OFF, disconnect the X1 harness connector at the turn signal/multifunction switch.
- Verify that a test lamp iluminates between the ground circuit terminal C and ground.
- Ignition ON, verify the scan tool Hazard Lamp Switch parameter is Inactive.
- Install a 3A fused jumper wire between the signal circuit terminal G and the ground circuit terminal C. Verify the scan tool Hazard Lamp Switch parameter is Active.
- 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 G for a short to ground. If the circuit tests normal, replace the BCM. |
| ⇒ | 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 BCM. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for BCM replacement, programming, and setup |
