Hazard Lamps Malfunction
Hazard Lamps Malfunction
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.
Diagnostic Fault Information
Circuit/System Description
The hazard flashers may be activated in any power mode. The hazard switch is located on the accessory control panel and is permanently grounded through ground G205. When the hazard switch is placed in the ON position, ground is applied through the hazard switch signal circuit to the instrument panel cluster (IPC). The IPC responds by sending a serial data message to the underhood electrical center (UEC) and the rear electrical center (REC) requesting the front and rear turn signal lamps be illuminated in an ON and OFF duty cycle. The UEC and REC respond by applying voltage to there respective turn signal control circuits illuminating the front and rear turn signal lamps ON and OFF. The IPC is also responsible for cycling both turn signal indicators ON and OFF. The IPC illuminates the hazard switch telltale by applying voltage to the hazard switch telltale signal circuit.
Reference Information
Schematic Reference
Exterior Lights Schematics (Exterior Lights Schematics)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
Exterior Lighting Systems Description and Operation (Exterior Lighting Systems Description and Operation)
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Verification
1. Ignition ON, observe the scan tool Hazard Warning Switch parameter while cycling the hazard switch ON and OFF. The parameter should change between Off and On.
• If the parameter does not change between the commanded states, refer to Hazard Lamps Malfunction.
2. Ignition ON, with a scan tool command the Hazard Warning LED Test ON and OFF. The hazard switch telltale indicator should turn ON and OFF when commanded.
• If the hazard switch telltale indicator does not illuminate when commanded, refer to Hazard Switch Telltale Malfunction.
3. Activate the hazard switch and observe the turn signal indicators on the IPC. Both turn signal indicators should cycle ON and OFF repeatedly.
• If the turn signal indicators do not cycle ON and OFF, refer to Hazard Lamp Indicators Malfunction.
Circuit/System Testing
Hazard Lamps Malfunction
1. Ignition OFF, disconnect the harness connector at the hazard switch.
2. Ignition OFF, verify a test lamp illuminates between B+ and the ground circuit terminal 2.
• If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
3. Ignition ON, verify the scan tool Hazard Warning Switch parameter is Off.
• If not the specified value, test the signal circuit terminal 6 for a short to ground. If the circuit tests normal, replace the IPC.
4. Install a 3A fused jumper wire between the signal circuit terminal 6 and ground. Verify the scan tool Hazard Warning Switch parameter is On.
• 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 IPC.
5. If all circuits test normal, replace the hazard switch.
Hazard Switch Telltale Malfunction
1. Ignition OFF, disconnect the harness connector at the hazard switch.
2. Ignition OFF, verify a test lamp illuminates between B+ and the ground circuit terminal 2.
• If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
3. Connect a test lamp between the control circuit terminal 15 and ground.
4. Command the Hazard Warning LED Test 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 open/high resistance. If the circuit tests normal, replace the IPC.
• If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the IPC.
5. If all circuits test normal, replace the hazard switch.
Hazard Lamp Indicators Malfunction
Ignition ON, with a scan tool perform the Turn Signal Telltale Test for the instrument panel cluster (IPC) and observe the left and right turn signal indicators.
If the turn signal indicators do not illuminate during the test or remain illuminated at all times, replace the IPC.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Front Seat Heater Switch Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for IPC replacement, setup, and programming