• | 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 X3 terminal 3 | B1395 03, B3600 03 | B1395 03, B3600 03 | -- | -- |
I/P Dimming Voltage Reference | B1395 03, B3600 03 | B3600 03 | -- | B1395 07 |
Instrument Panel Lamps Dimmer Switch Signal | B3600 03 | B3600 03 | 1 | -- |
1. Interior Backlighting Inoperative |
The 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 brightness 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 I/P lamps supply voltage circuit and the LED dimming supply circuit to all related interior lamps, illuminating them to the desired level of brightness.
The ignition is ON.
The BCM detects a voltage that is lower than 9 volts on the I/P dimming voltage reference circuit.
The BCM detects a voltage that is greater than 14 volts on I/P dimming voltage reference circuit.
The I/P lamps are not illuminated.
• | The condition responsible for setting the DTC no longer exists. |
• | A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred. |
Interior Lights Dimming Schematics
Lighting Systems Connector End Views
Ignition ON, cover the ambient light sensor, vary the interior lamp dimming switch from dim to full bright. The I/P lamps should dim and then become full bright.
⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. |
⇒ | If less than the specified value, test the voltage reference circuit for a short to ground or an open/high resistance. If the circuit test normal, replace the BCM. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for BCM replacement, setup, and programming |