1. Turn the ignition switch to RUN.
2. Use the scan tool in order to attempt to establish communication with the following components on the class 2 data link:

•	The body control module (BCM)

•	The electronic brake control module (EBCM)

•	The instrument cluster

Are all of the modules communicating with the scan tool?

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Go to Step 2

Go to Scan Tool Does Not Communicate with Class 2 Data Line in Wiring Systems

1. Ensure that the master cylinder fluid level is at the FULL mark. Refer to Master Cylinder Reservoir Filling .
2. Select instrument panel cluster, special functions, lamp test.
3. Select brake lamp.
4. Command the OFF.

Does the brake warning lamp turn OFF?

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Go to Step 3

Go to Step 12

1. Ensure that the master cylinder fluid level is at the FULL mark. Refer to Master Cylinder Reservoir Filling .
2. Disconnect the brake fluid level switch.

Does the brake warning lamp turn off?

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Go to Step 4

Go to Step 5

Replace the brake fluid level switch.

Is the repair complete?

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System OK

Go to Step 12

Disconnect the park brake switch.

Does the brake warning lamp turn off?

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Go to Step 6

Go to Step 7

Replace the park brake switch.

Is the repair complete?

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System OK

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Disconnect the EBCM.

Does the brake warning lamp turn off?

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Go to Diagnostic System Check - ABS

Go to Step 8

Disconnect the BCM. Refer to Body Control Module Replacement in Body Control System.

Does the brake warning lamp turn off?

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Go to Step 9

Go to Step 11

Locate the short to ground on CKT 1134 (LT BLU) between the park brake switch and the BCM.

Did you find a short to ground?

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Go to Step 10

Go to Step 11

Repair the short to ground on CKT 1134 (LT BLU) between the park brake switch and the BCM.

Is the repair complete?

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System OK

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Replace the BCM. Refer to Body Control Module Replacement in Body Control Systems.

Is the repair comlete?

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System OK

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Replace the instrument cluster. Refer to Instrument Cluster Replacement in Instrument Panel, Gauges and Console.

Is the repair complete?

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Go to Instrument Cluster System Check .

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