Circuit Description
The body control module (BCM) receives a variable voltage from the instrument panel lamp dimmer switch. The BCM uses this signal in order to vary the illumination level of the instrument panel lamps. The instrument panel dimming lamps output from the BCM is a pulse width modulated voltage supply used to light the instrument panel lamps. If a malfunction occurs in the instrument panel dimming lamps output circuit, this DTC is set.
Conditions for Running the DTC
The park lamp input is active (park or headlamps on).
Conditions for Setting the DTC
Any of the following conditions will set this DTC:
| • | The instrument panel dimming lamps output is open for 125 milliseconds. |
| • | The instrument panel dimming lamps output is shorted to ground for 125 milliseconds. |
| • | The instrument panel dimming lamps output is shorted to battery positive voltage for 125 milliseconds. |
Action Taken When the DTC Sets
| • | If the instrument panel dimming lamps output is open, the instrument panel lamps will not illuminate. |
| • | If the instrument panel dimming lamps output is shorted to ground, the instrument panel lamps will not illuminate. |
| • | If the instrument panel dimming lamps output is shorted to battery positive voltage, the instrument panel lamps will illuminate at full intensity. |
Conditions for Clearing the DTC
| • | The conditions for setting the DTC are no longer present. |
| • | A history DTC clears after 100 malfunction free ignition cycles. |
| • | The BCM receives the clear code command from the scan tool. |
Diagnostic Aids
If the DTC is a history DTC, the malfunction may be intermittent. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Interior Lights Dimming Schematics | |||
1 | Did you perform the Lighting System Diagnostic System Check? | Go to Step 2 | |
2 |
Do the instrument panel lamps stay on at full intensity? | Go to Step 8 | Go to Step 3 |
3 | Are all of the instrument panel lamps inoperative? | Go to Step 4 | Go to Step 6 |
4 | Test for a short to ground or open in the instrument panel dimming lamps output circuit between the BCM and each individual lamp connected to the output circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 5 |
5 | Inspect for poor connections at the harness connector of the body control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 11 |
6 |
Does the testlamp illuminate? | Go to Step 7 | Go to Step 9 |
7 | Test for an open in the instrument panel dimming lamp ground circuit at the affected component. Refer to Circuit Testing and in Wiring Systems Did you find and correct the condition? | Go to Step 12 | Go to Step 10 |
8 | Repair a short to voltage in the instrument panel dimming lamps output circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 12 | -- |
9 | Repair the open in the instrument panel dimming lamp output circuit at the affected component. Refer to Wiring Repairs in Wiring Systems Did you complete the repair? | Go to Step 12 | -- |
10 | Replace the inoperative component which causes this DTC to be set. Refer to the appropriate repair procedure. Did you complete the replacement? | Go to Step 12 | -- |
11 |
Important: Perform the set up procedure for the body control module. Replace the body control module. Refer to Body Control Module Replacement in Body control System. Did you complete the replacement? | Go to Step 12 | -- |
12 |
Does the DTC reset? | Go to Step 2 | System OK |
