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.

### DTC Descriptors

DTC B096A 01: Hazard Lamps Switch Backlighting Circuit to Voltage
DTC B096A 02: Hazard Lamps Switch Backlighting Short to Ground
DTC B096A 04: Hazard Lamps Switch Backlighting Circuit Open

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Interior backlighting control | B096A 02** | B096A 04** | B096A 01* | --
* Hazard backlighting at full Intensity and cannot be dimmed ** Hazard backlighting do not Illuminate

### Circuit/System Description

The body control module (BCM) supplies a voltage reference through the instrument panel cluster dimming voltage reference circuit to the instrument panel cluster lamps dimmer switch, which is part of the headlamp switch. When the dimmer switch is placed in a desired brightness position, reference voltage is applied through the dimmer switch rheostat and the cluster lamps dimmer switch signal circuit to the BCM. The BCM interprets this voltage signal, then applies a pulse width modulated (PWM) voltage through the instrument panel cluster lamps supply voltage circuit and the LED dimming supply circuit to all related interior lamps, illuminating them to the desired level of brightness.

### Conditions for Running the DTC

The ignition is ON.

### Conditions for Setting the DTC

#### B096A 01

The BCM detects a short to battery on the LED backlight lamp control circuit.

#### B096A 02

The BCM detects a short to ground on the LED backlight lamp control circuit.

#### B096A 04

The BCM detects an open circuit on the LED backlight lamp control circuit.

### Action Taken When the DTC Sets

The BCM will not dim or illuminate any LED backlighting supplied by the backlight lamp control circuits.

### Conditions for Clearing the DTC

• | The condition responsible for setting the DTC no longer exists.

• | A history DTC will clear once 100 consecutive malfunction ignition cycles have occurred.

### Reference Information

#### Schematic Reference

Interior Lights Dimming Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Interior 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, vary the interior lamp dimming switch from dim to full bright. The interior backlighting should dim and then become full bright.

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the S26 Hazard Warning Switch.
2. Test for less than 5 Ω between the ground circuit terminal 2 and ground.

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

3. Connect a test LED between the control circuit of the appropriate component and ground.
4. Ignition ON, vary the interior lamp dimming switch from dim to full bright. The test LED should dim and then become full bright.

⇒ | If the LED cannot be dimmed test the control circuit for a short to voltage or replace the K9 Body Control Module (BCM).

⇒ | If the LED do not emit at all test the control circuit for open/high resistance or replace the K9 Body Control Module (BCM).

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