• | 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 | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
B+, BCM X2 Terminal 2 | B2652 00 | B2652 00 | -- | -- |
I/P Lamps Control | B2652 00 | 2 | 1 | -- |
1. Interior Backlighting Does Not Dim 2. Interior Backlighting Inoperative |
The body control module (BCM) supplies a voltage reference through the instrument panel (I/P) dimming voltage reference circuit to the interior lamp dimmer switch, which is part of the headlamp switch. When the dimmer switch is placed in a desired position, reference voltage is applied through the dimmer switch rheostat and the I/P 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 lamp control circuits illuminating the components listed below.
• | Hazard Switch |
• | I/P Cluster |
• | Power Window Switches |
• | Sunroof Switch |
• | Garage Door Opener Transmitter |
• | The ignition is ON. |
• | The headlamps or park lamps ON. |
The BCM detects a short to ground on the instrument panel lamps control circuit.
The BCM does not attempt to illuminate the instrument panel lamps.
A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.
Interior Lights Dimming Schematics
Interior Lighting Systems Description and Operation
Control Module References for scan tool information
Ignition ON, command Incandescent Dimming ON with a scan tool. The Incandescent Relay Command parameter should display On and the Incandescent Dimming should illuminate.
⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuits listed below for a short to ground. |
• | Instrument panel lamp control circuit terminal 3 X2 |
• | Instrument panel lamp control circuit terminal 3 X6 |
• | Instrument panel lamp control circuit terminal 3 X2 |
• | Instrument panel lamp control circuit terminal 3 X6 |
⇒ | If the DTC resets, test the control circuits for a short to ground. If the circuits test normal, replace the BCM. |
⇒ | If the DTC resets, test or replace the component responsible for setting the DTC. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for BCM replacement, setup, and programming |