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 Fuse Voltage Supply Circuit | 1 | 1 | -- | --
Hazard Switch Signal Circuit | 1 | 1 | -- | --
1. Hazard Lamps Inoperative

### Circuit/System Description

There is constant voltage that is supplied to the hazard switch. The hazard switch (when engaged) supplies voltage to the park/turn signal lamps. The turn signal switch in the headlamp switch portion of the turn signal multifunction switch also is provided voltage from the hazard switch circuit after the turn signal circuit. Depending on the location of the hazard switch will determine which fuse the turn/hazard circuit will be powered.

### Diagnostic Aids

• | The hazard switch open/high resistance.

• | The turn signal fuses shorted to ground, open/high resistance located within the I/P fuseblock

• | A short to voltage or open/high resistance in the hazard switch supply circuit.

### Reference Information

#### Schematic Reference

Exterior Lights Schematics

#### Connector End View Reference

Lighting Systems Connector End Views

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

• | Scan Tool Data Definitions

• | Scan Tool Data List

• | Scan Tool Output Controls

### Circuit/System Verification

Turn the hazards ON with the hazard switch. The hazard flasher module should make a clicking noise while the hazards start to flash.

### Circuit/System Testing

#### Hazard Switch Circuit Testing

1. Ignition OFF, disconnect the harness connector at the hazard switch terminal B.
2. Test for less than 1 ohm of resistance between the ground circuit and ground.

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

3. Verify the hazard lights are OFF.

⇒ | If the hazard lights are not OFF, test the signal circuit for a short to ground. If the circuit tests normal, replace the hazard flasher module.

4. Install a 3-amp fused jumper wire between the hazard fuse signal circuit and one of the circuits for the hazard lamps. Verify the hazard lights are ON. Repeat for the opposite hazard lamp.

⇒ | If the hazard lights are not ON, test the signal circuit of the hazard switch for a short to voltage or an open/high resistance.

5. If all circuits test normal, test or replace the hazard switch.

### Component Testing

#### Hazard Switch Testing

1. Ignition OFF, disconnect the harness connector at the hazard switch, terminal B.
2. Test for infinite resistance between the signal terminals and the voltage supply terminal with the switch in the open position.

⇒ | If less than infinite resistance, replace the hazard switch.

3. Test for less than 1.5 ohms between the signal terminals and the voltage supply terminal with the switch in the closed position.

⇒ | If greater than the specified range, replace the hazard switch.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Hazard Warning Switch Replacement

• | Control Module References for BCM replacement, setup, and programming.