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.

### Circuit/System Description

The flash to pass switch simultaneously activates the headlamps on signal and the high beam signal inputs to the body control module (BCM). The BCM monitors the signal circuit voltage and when the flash to pass switch is activated the switch contacts close the headlamps on and high beam signal circuits to ground.

### Reference Information

#### Schematic Reference

Headlights/Daytime Running Lights (DRL) 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

Ignition ON, observe the scan tool headlamp on switch and high beam select switch parameters while operating the flash to pass switch on and off. The readings should change between active and inactive.

### Circuit/System Testing

1. Ignition OFF, disconnect the inline harness connector X204.
2. Test for less than 5 ohms between the ground circuit terminal B10 and ground.

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

3. Ignition ON, verify the scan tool headlamp on switch parameter is inactive.

⇒ | If not the specified value, test the signal circuit terminal A10 for a short to ground. If the circuit tests normal, replace the BCM.

4. Verify the scan tool high beam select switch parameter is inactive.

⇒ | If not the specified value, test the signal circuit terminal A11 for a short to ground. If the circuit tests normal, replace the BCM.

5. Install a 3A fused jumper wire between the signal circuit terminal A10 and the ground circuit terminal B10. Verify the scan tool headlamp on 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 BCM.

6. Install a 3A fused jumper wire between the signal circuit terminal A11 and the ground circuit terminal B10. Verify the scan tool high beam select 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 BCM.

7. If all circuits test normal, test or replace the turn signal/multifunction switch.

### Component Testing

#### Flash to Pass Switch Test

1. Ignition OFF, disconnect the inline harness connector X204.
2. Test for infinite resistance between the signal terminal A10 and the low reference terminal B10.

⇒ | If not the specified value, replace the turn signal/multifunction switch.

3. Test for infinite resistance between the signal terminal A11 and the low reference terminal B10.

⇒ | If not the specified value, replace the turn signal/multifunction switch.

4. Test for less than 5 ohms between the signal terminal A10 and the low reference terminal B10 while activating the flash to pass switch.

⇒ | If greater than the specified range, replace the turn signal/multifunction switch.

5. Test for less than 5 ohms between the signal terminal A11 and the low reference terminal B10 while activating the flash to pass switch.

⇒ | If greater than the specified range, replace the turn signal/multifunction switch.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Turn Signal Multifunction Switch Replacement

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