B3596

DTC B3596

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.

DTC Descriptor
DTC B3596 00
- Hazard Lamps Request Circuit Malfunction

Diagnostic Fault Information





Circuit/System Description

The hazard flashers may be activated in any power mode. The hazard switch signal circuit is momentarily grounded when the hazard switch is pressed. The body control module (BCM) supplies battery voltage to all turn signal lamps in an ON and OFF duty cycle. When the hazard switch is activated, the BCM sends a serial data message to the instrument cluster requesting both turn signal indicators to be cycled ON and OFF.

Conditions for Running the DTC

Hazard warning switch activated.

Conditions for Setting the DTC

Hazard warning switch stuck.

Action Taken When the DTC Sets

Hazard flashers malfunction.

Conditions for Clearing the DTC

The condition for setting the DTC is no longer present.

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 (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Verification

Ignition ON, observe the scan tool Hazard Warning Switch parameter. While pressing and releasing the hazard switch, the scan tool parameter should toggle between Active and Inactive.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the A20 radio/HVAC controls.
2. Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Test for less than 10 ohm between the ground circuit terminal 17 and ground.

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

3. Ignition ON, verify the scan tool Hazard Warning Switch parameter is Inactive.

• If not the specified value, test the signal circuit terminal 16 for a short to ground. If the circuits tests normal, replace the K9 BCM.

4. Install a 3 A fused jumper wire between the signal circuit terminal 16 and the ground circuit terminal 17. Verify the scan tool Hazard Warning 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 BCM.

5. If all circuits test normal, test or replace the A20 radio/HVAC controls.

Component Testing

Static Test
1. Ignition OFF, disconnect the harness connector at the A20 Radio/HVAC Controls.
2. Test for infinite resistance between the terminal 16 and terminal 17.

• If less than the specified value, replace the A20 Radio/HVAC Controls.

3. Press and hold the Hazard Warning Switch, test for less than 5 ohm between the terminal 16 and terminal 17.

• If not within the specified range, replace the A20 Radio/HVAC Controls.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Radio Control Assembly Replacement (Radio Control Assembly Replacement)
* Control Module References (Programming and Relearning) for BCM replacement, setup and programming