For 1990-2009 cars

### Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

1. If the fuse in the jumper opens when you perform this test, the signal circuit of the brake fluid level switch is shorted to voltage.

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Brake Warning System Schematics Connector End Views Reference: Hydraulic Brake Connector End Views or Instrument Panel, Gages, and Console Connector End Views or Body Control System Connector End Views
1 | Did you review the hydraulic brakes operation and perform the necessary inspection? | Go to Step 2 | Go to Symptoms - Hydraulic Brakes
2 | Inspect the brake fluid level. Is the brake fluid level OK? | Go to Step 3 | Go to Brake Fluid Loss
3 |

1. Turn ON the ignition, with the engine OFF.
2. Disengage the park brake.
3. With a scan tool, observe the Park Brake Switch parameter in the BCM Inputs data list.

Does the scan tool indicate that the Park Brake Switch parameter is Inactive?

Go to Step 4

Go to Step 5

4 | With a scan tool, observe the Brake Warning Lamp parameter in the IPC Inputs data list. Does the scan tool indicate that the Brake Warning Lamp parameter is ON? | Go to Step 12 | Go to Step 6
5 |

1. Disconnect the park brake warning lamp switch.
2. With a scan tool, observe the Park Brake Switch parameter.

Does the scan tool indicate that the Park Brake Switch parameter is Inactive?

Go to Step 9

Go to Step 7

6 |

1. Disconnect the brake fluid level switch.
2. With a scan tool, observe the Brake Warning Lamp parameter.

Does the scan tool indicate that the Brake Warning Lamp parameter is ON?

Go to Step 10

Go to Step 8

7 |

1. Turn OFF the ignition.
2. Test the signal circuit of the park brake warning lamp switch for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 17

Go to Step 11

8 |

1. Turn OFF the ignition.
2. Test the signal circuit of the brake fluid level switch for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 17

Go to Step 11

9 | Inspect for poor connections at the harness connector of the park brake warning lamp switch. 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 17 | Go to Step 13
10 | Inspect for poor connections at the harness connector of the brake fluid level switch. 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 17 | Go to Step 14
11 | 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 17 | Go to Step 15
12 | Inspect for poor connections at the harness connector of the instrument Panel cluster. 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 17 | Go to Step 16
13 | Replace the park brake warning lamp switch. Refer to Stop Lamp Switch Replacement in Park Brake. Did you complete the repair? | Go to Step 17 | --
14 | Replace the brake fluid level switch. Refer to Brake Fluid Level Indicator Switch Replacement . Did you complete the repair? | Go to Step 17 | --
15 | Replace the Body Control Module. Refer to Body Control Module Replacement in Body Control System. Did you complete the repair? | Go to Step 17 | --
16 | Replace the instrument cluster (IPC). Refer to Instrument Cluster Replacement in Instrument Panel, Gages and Console. Did you complete the repair? | Go to Step 17 | --
17 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 2