Circuit Description
The body control module (BCM) monitors the instrument panel (I/P) dimming voltage on the I/P lamp fuse supply voltage 2 circuit from the dimmer switch, or thumb wheel, part of the headlamp and panel dimmer switch. The dimmer switch controls the I/P dimming by sending a signal to the BCM on the I/P lamp fuse supply voltage 2 circuit in order to indicate the position of the thumb wheel when the headlamps are ON. The dimmer switch also provides dimming for the backlighting of the instrument cluster , radio and the overhead console.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B2613 Passenger Compartment Dimming Circuit High
Conditions for Running the DTC
| • | The battery voltage must be between 9-16 volts. |
| • | Ignition switch in the RUN position. |
| • | The park lamp switch, which is part of the headlamp and panel dimmer switch, must be in the OFF or AUTO position and the ambient light sensor must be in the DARK state. |
| • | The park brake released. |
Conditions for Setting the DTC
To set B2613, the following conditions must be present:
| • | The I/P lamp fuse supply voltage 2 circuit is shorted to battery voltage. |
| • | The above conditions must be met for 0.5 seconds. |
Action Taken When the DTC Sets
The I/P lights remain full bright at all times.
Conditions for Clearing the MIL/DTC
| • | A current DTC will clear at the next fault free ignition cycle. |
| • | A history DTC will clear after 100 consecutive ignition cycles without a fault present. |
| • | Use a scan tool in order to clear history and current DTCs. |
Diagnostic Aids
Perform a visual inspection for loose or poor connections at all related components. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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This step tests for the proper operation of the circuit in the low voltage range.
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This step tests for the proper operation of the circuit in the high voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to ground.
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This step tests for a short to voltage in the 12-volt reference circuit.
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After replacement of the BCM you must calibrate the new module for proper operation.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Schematic Reference: Interior Lights Dimming Schematics Connector End View Reference: Lighting Systems Connector End Views or Computer/Integrating Systems Connector End Views in Computer/Integrating Systems | ||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
2 |
Does the scan tool indicate that the dimming potentiometer parameter is within the specified range? | 0.1-13.5 V | Go to Diagnostic Aids | Go to Step 3 |
Does the scan tool indicate that the Dimming Potentiometer parameter is less than the specified value? | 0.1 V | Go to Step 4 | Go to Step 9 | |
Does the scan tool indicate that the Dimming Potentiometer parameter is greater than the specified value? | 13.5 V | Go to Step 5 | Go to Step 7 | |
Does the voltage measure less than the specified value? | 0.1 V | Go to Step 10 | Go to Step 6 | |
6 | Test the 12-volt reference circuit of the dimming potentiometer for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 11 |
7 | Test the 12-volt reference circuit of the dimming potentiometer for a short to ground, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 8 |
8 | Test the signal circuit of the dimming potentiometer for a short to ground, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 11 |
9 | Test the signal circuit of the dimming potentiometer for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 11 |
10 | Inspect for poor connections at the harness connector of the dimming potentiometer. 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 14 | Go to Step 12 |
11 | Inspect for poor connections at the harness connector of the BCM. 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 14 | Go to Step 13 |
12 | Replace the headlamp and panel dimmer switch. Refer to Headlamp Switch Replacement . Did you complete the replacement? | -- | Go to Step 14 | -- |
Replace the BCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 14 | -- | |
14 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
