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 B3600 03 : Voltage Below ThresholdDTC B3600 07: Voltage Above Threshold
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Instrument Panel Lamp Dimmer Switch Signal | B3600 03 | B3600 03 | B3600 07 | B3600 03 or B3600 07 |
Reference Voltage | B1395 03 and B3600 07 | B1395 03 and B3600 07 | B1395 07 | B1395 03, B1395 07 and B3600 03, B3600 07 |
Circuit/System Description
Voltage for the interior backlighting components is supplied from the body control module (BCM). The BCM applies a voltage reference through the 12-volt reference circuit to the headlamp and panel dimmer switch. When the dimming switch is placed in the desired position, the dimmed voltage setting is applied from the headlamp and panel dimmer switch through the instrument panel (I/P) lamp dimmer switch signal circuit to the BCM. The BCM then applies the dimmed voltage to the lamp supply voltage circuits and they are dimmed to the correct level.
Conditions for Running the DTC
The ignition is ON.
Conditions for Setting the DTC
B3600 03
The BCM detects a voltage that is lower than 0.10 volt on the I/P lamp dimmer switch signal circuit.
B3600 07
The BCM detects a voltage that is higher than 4.97 volts on the I/P lamp dimmer switch signal circuit.
Action Taken When the DTC Sets
The I/P lamps are not illuminated.
Conditions for Clearing the DTC
The BCM clears this code from current when the fault is removed from the system.
Reference Information
Schematic Reference
Interior Lights Dimming Schematics
Connector End View Reference
Lighting Systems Connector End Views
Electrical Information Reference
Scan Tool Reference
Circuit/System Verification
Ignition ON, headlamp switch to HEAD, vary the interior lamp dimming switch from dim to full bright. The I/P lamps should dim and then become full bright.
Circuit/System Testing
- Ignition ON and clear the DTC. Use the scan tool Incandescent Dimming output control to adjust the dimming level of the I/P lamps from low to high.
- Monitor the Dimming Control Signal voltage parameter in the scan tool BCM data list while adjusting the dimmer switch from high to low.
- If the voltage is above 4.97 volts, test for a short to voltage in the I/P lamp dimmer switch signal circuit.
- If the voltage drops below 0.10 volt, test for a short to ground, open, or high resistance in the I/P lamp dimmer switch signal circuit.
| ⇒ | If the lamps cannot be controlled with the scan tool, replace the BCM. |
| ⇒ | If the circuit/connections test normal, replace the headlamp and panel dimmer switch. |
| ⇒ | If the circuit/connections test normal, replace the headlamp and panel dimmer switch. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for BCM replacement, setup, and programming |
