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
--- | --- | --- | --- | ---
Reading Lamp Voltage Supply Circuit | 1 | 1 | -- | --
Reading Lamp Ground Supply Circuit | -- | 1 | 1 | --
Reading Lamp Assembly | 1, 2 | 1 | 1, 2 | --
1. Reading Lamp Inoperative 2. Reading Lamp Always ON

### Circuit/System Description

When the roof rail reading lamps switches are in the OFF position, the body control module (BCM) supplies the roof rail reading lamps park lamps with voltage and ground. The BCM maintains voltage and ground for a set amount of time for the illuminated entry option. When the roof rail reading lamp switch is in the ON position the BCM only supplies the voltage for the roof rail lamps

### Diagnostic Aids

A short to ground, a short to voltage or an open in the following location may cause a malfunction to occur:

• | The reading lamp switch supply circuit

• | The reading lamp switch ground circuit

• | The reading lamp switch

### Reference Information

#### Schematic Reference

Interior Lights Schematics

#### Connector End View

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

Ignition ON, turn the reading lamps ON by turning the switch on the reading lamps to the ON position. The reading lamps should turn ON.

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the reading lamp switch.
2. Test for less than 1.0 ohm of resistance between the ON circuit and ground.

⇒ | If greater than 1.0 ohm, test the ON circuit for an open/high resistance.

3. Install a test lamp between the signal circuit and ground. Verify the test lamp turns ON.

⇒ | If the test lamp does not turn ON, test the signal circuit of the reading lamp switch for a short to ground or an open/high resistance.

4. If all circuits test normal, test or replace the reading lamp assembly or the reading lamp bulb.

### Component Testing

#### Reading Lamp Assembly Testing

1. Ignition OFF, disconnect the harness connector at the reading lamp assembly.
2. Test for less than 2.0 ohms between the signal terminal and the ON terminal with the switch in the ON position.

⇒ | If greater than 2.0 ohms, replace the reading lamp assembly.

#### Reading Lamp, Light Bulb Testing

1. Ignition OFF, remove the reading lamp bulb.
2. Test for 1.0 to 4.5 ohms of resistance between the control terminal and the voltage supply terminal of the reading lamp bulb.

⇒ | If the resistance is not within the specified range, replace the reading lamp bulb.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Reading Lamp Bulb Replacement