Brake Warning Indicator Malfunction
Brake Warning Indicator Malfunction
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.
Diagnostic Fault Information
Circuit/System Description
The I/P cluster B+ circuit provides voltage to all malfunction indicator lights within the I/P cluster. The park brake switch is normally open when the park brake lever is not engaged and the switch within the brake master cylinder reservoir is normally open when sufficient brake fluid is contained within the reservoir. When the fluid drops to a critical level or if the parking brake is applied, the respective switch closes providing a ground to the park brake indicator circuit causing the lamp to illuminate.
Reference Information
Schematic Reference
Hydraulic Brake Schematics ([1][2]Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
Brake Warning System Description and Operation (Brake Warning System Description and Operation)
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
Circuit/System Verification
1. Ignition ON, inspect the fluid level within the brake master cylinder reservoir. The brake fluid should be above the MIN level in the reservoir.
• If the fluid level is below the MIN level, adjust to the proper level.
2. Press the release button on the park brake release lever and verify the park brake is not engaged.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the park brake switch.
2. Disconnect the harness connector at the brake fluid level switch.
3. Test for less than 1 ohm between the ground circuit terminal 2 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
4. Ignition ON, verify the park brake indicator is not illuminated.
• If the park brake indicator is illuminated, test the control circuit terminal 1 for a short to ground. If the circuit tests normal, replace the I/P cluster.
5. Connect a 10 A fused jumper wire between the control circuit terminal 1 at the park brake switch and ground. Verify the park brake indicator lamp is illuminated.
• If the park brake indicator lamp is not illuminated, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the I/P cluster.
6. Ignition OFF, connect the harness connector at the park brake switch.
7. Ignition ON, verify the park brake indicator lamp is not illuminated.
• If the park brake indicator lamp is illuminated, test or replace the park brake switch.
8. If all circuits test normal, test or replace the brake fluid level switch.
Component Testing
Park Brake Switch
1. Ignition OFF, disconnect the harness connector at the park brake switch.
2. Test for infinite resistance between the signal terminal 1 and the ground with the park brake released.
• If less than the specified value, replace the park brake switch.
3. Test for less than 1 ohm between the signal terminal 1 and ground with the park brake applied.
• If greater than the specified range, replace the park brake switch.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Instrument Cluster Replacement (Service and Repair)
* Master Cylinder Reservoir Replacement (Master Cylinder Reservoir Replacement)
* Parking Brake Lever Replacement (Service and Repair)