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 Descriptor
DTC B2624 00: Dimming Display Pulse Width Modulation (PWM) Input Circuit LowDTC B2624 00: Dimming Display Pulse Width Modulation (PWM) Input Circuit Open
DTC B2624 00: Dimming Display Pulse Width Modulation (PWM) Input Circuit High
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Body Control Module B+ | B2622 00 | B2622 00 | B2622 00 | -- |
I/P Lamps Dimmer Switch Signal | B2622 00 | 2 | B2623 00 | -- |
Accessory Switch Control | B2622 00 | 1 | B2623 00 | -- |
Hazard Switch Control | B2622 00 | 1 | B2623 00 | -- |
HVAC Control Module Control | B2622 00 | 1 | B2623 00 | -- |
I/P DImmer Control | B2624 00 | B2624 00 | B2624 00 | -- |
Accessory Switch Ground | -- | 1 | -- | -- |
Hazard Switch Ground | -- | 1 | -- | -- |
HVAC Control Module Ground | -- | 1 | -- | -- |
Headlamp and Panel DImmer Switch Low Reference | 2 | 2 | 2 | -- |
| ||||
Circuit/System Description
The instrument panel (I/P) lamp dimmer switch is used to increase and decrease the brightness of the interior backlighting components. The I/P dimmer switch provides a voltage signal that will increase as the brightness of the lights are increased and decrease as the brightness of the lights are decreased. The body control module (BCM) provides a low reference signal and a B+ voltage reference to the I/P dimmer switch. When the I/P dimmer switch is placed in the desired position, the dimmed voltage setting is applied from the I/P dimmer switch through the I/P dimmer switch signal circuit to the BCM. The BCM interprets the signal and applies the dimmed voltage to the I/P lamps supply voltage circuit and the interior backlighting components dim to the requested level.
Conditions for Running the DTC
The battery voltage must be between 9-16 volts.
Conditions for Setting the DTC
When the BCM recieves a voltage signal equal to or greater than 4.86 volts for more than one second.
Action Taken When the DTC Sets
The I/P illumination lamps dimming will not operate and the lights will be at full intensity always.
Conditions for Clearing the DTC
| • | This DTC will clear on current status after the condition for setting the fault is corrected. |
| • | A history DTC will clear after 100 consecutive ignition cycles without a fault present. |
Reference Information
Schematic Reference
Interior Lights Dimming Schematics
Connector End View Reference
Description and Operation
Interior Lighting Systems Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the headlamp and panel dimmer switch.
- Test for less than 5 ohms between the low reference circuit terminal 3 and ground.
- Ignition ON, verify the scan tool dimming potentiometer is greater than 4.5 volts.
- Install a 3A fused jumper wire between the signal circuit terminal 14 and the low reference circuit terminal 3. Verify the scan tool dimming potentiometer is less than 0.6 volts.
- If all circuits test normal, test or replace the headlamp and panel dimmer switch.
| ⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. |
| ⇒ | If not the specified value, test the signal circuit terminal 14 for a short to low reference. If the circuit tests normal, replace the BCM. |
| ⇒ | If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for BCM replacement, setup, and programming |
