For 1990-2009 cars

### 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 | 1 | 1 | --
Hazard Switch Indicator Signal | 3 | 3 | 4 | --
Hazard Switch Ground | -- | 1, 2 | -- | --
1. Hazard Lamps Inoperative 2. Hazard Lamps always ON 3. Hazard Switch Indicator Inoperative 4. Hazard Switch always ON

### Circuit/System Description

The hazard flashers may be activated in any power mode. The hazard switch is permanently grounded. 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 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.

### Reference Information

#### Schematic Reference

Exterior Lights Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Exterior Lighting Systems Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Testing

#### Hazard Lamps Malfunction

1. Ignition OFF, disconnect the harness connector at the S26 Hazard Warning Switch.
2. Ignition OFF, verify a test lamp illuminates between B+ and the ground circuit terminal 7.

⇒ | If the test lamp does not illuminate, test the ground circuit for an open/high resistance.

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

⇒ | If not the specified value, test the signal circuit terminal 10 for a short to ground. If the circuit tests normal, replace the K9 Body Control Module (BCM).

4. Install a 3 A fused jumper wire between the signal circuit terminal 10 and ground. Verify the scan tool Hazard Lamp 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 (BCM).

5. If all circuits test normal, replace the S26 Hazard Warning Switch.

#### Hazard Switch Indicator Malfunction

1. Ignition OFF, disconnect the harness connector at the S26 Hazard Warning Switch.
2. Ignition OFF, verify a test lamp illuminates between B+ and the ground circuit terminal 7.

⇒ | If the test lamp does not illuminate, test the ground circuit for an open/high resistance.

3. Install a 3 A fused jumper wire between the signal circuit terminal 10 and ground. Verify a test lamp illuminates between the signal circuit terminal 5 and ground in an ON and OFF duty cycle.

⇒ | If the test lamp does not illuminate, test the signal circuit terminal 5 for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module (BCM).

⇒ | If the test lamp does illuminate permanently, test the signal circuit terminal 5 for a short to voltage. If the circuit tests normal, replace the K9 Body Control Module (BCM).

4. If all circuits test normal, replace the S26 Hazard Warning Switch.

#### Hazard Lamp Indicators Malfunction

Ignition ON, command the All Indicators test ON and OFF with the scan tool, verify both turn signal indicators changes between turn ON and OFF.

⇒ | If both turn signal indicators changes between illuminate and not illuminate during the test, replace the K9 Body Control Module (BCM.

⇒ | If one or both turn signal indicators do not illuminate during the test or remain illuminated at all times, replace the P16 Instrument Cluster.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Hazard Warning Switch Replacement

• | Control Module References for BCM or instrument cluster replacement, setup, and programming