GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Isuzu 🢒 2008 🢒 I-370 🢒 Body Systems 🢒 Lighting 🢒 Hazard Lamps Malfunction

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

1

1

--

--

Hazard Lamp Indicator Control

1

1

1

--

Turn Signal Lamp Control

B0527, B0532

B0528, B0533

B0528, B0533

--

Hazard Switch Ground

--

1

--

--

Turn Signal Lamp Ground

--

1

--

--

1. Hazard Lamps 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 ground G106. 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 and indicators in an ON and OFF duty cycle.

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 Verification
  1. 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.
    2. ⇒If the reading does not change between Active and Inactive, refer to Hazard Lamp Switch Malfunction.
  2. Ignition ON, turn the hazard switch to the ON position. The hazard lamps should turn ON and OFF.
    3. ⇒If the readings do not change, refer to Hazard Lamp Malfunction.
  3. Ignition ON, turn the hazard switch to the ON position. The hazard lamp indicators should turn ON and OFF.
    4. ⇒If the indicatiors do not flash ON and OFF or remain ON or OFF at all times, refer to Hazard Lamp Indicator Malfunction.

Circuit/System Testing

Hazard Lamp Switch Malfunction

  1. Ignition OFF, disconnect the harness connector at the hazard switch.
  2. Test for less than 5 ohms between the ground circuit terminal B and ground.
    3. ⇒If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool hazard lamp switch parameter is Inactive.
    4. ⇒If not the specified value, test the signal circuit terminal C for a short to ground. If the circuit tests normal, replace the BCM.
  4. Install a 3A fused jumper wire between the signal circuit terminal C and the ground circuit terminal B. Verify the scan tool hazard lamp switch parameter is Active.
    5. ⇒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.
  5. If all circuits test normal, test or replace the hazard switch.

Hazard Lamp Malfunction

  1. Ignition OFF, disconnect the harness connector at the inoperative hazard lamp.
  2. Test for less than 5.0 ohms between the ground circuit terminal G and ground.
    3. ⇒If more than the specified value, test the ground circuit for an open/high resistance.
  3. Ignition OFF, connect a test lamp between the control circuit terminal A and ground.
  4. Hazard lamp switch ON, the test lamp should turn ON and OFF.
    5. ⇒If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
    ⇒If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If all circuits test normal, replace the BCM.
  5. If all circuits test normal, replace the inoperative hazard lamp.

Hazard Lamp Indicator Malfunction

  1. Ignition OFF, disconnect the harness connector at the instrument panel cluster.
  2. Connect a test lamp between the ground circuit terminal 4 and B+. The test should illuminate.
    3. ⇒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 6 and the ground circuit terminal 4. Turn the hazard switch to the ON position. The test lamp should turn ON and OFF.
    4. ⇒If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
    ⇒If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  4. Connect a test lamp between the control circuit terminal 7 and the ground circuit terminal 4. Turn the hazard switch to the ON position. The test lamp should turn ON and OFF.
    5. ⇒If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
    ⇒If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, replace the instrument panel cluster.

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