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Home >> GMC >> 2006 >> Sierra 1500 HD, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1122 (Hydraulic Brake System) >> Diagnostic Information and Procedures >> Brake Warning Indicator Malfunction >> Component Testing

Component Testing

WARNING: This page is about a different car, the 2008 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.

Brake Fluid Level Switch 

  1. Inspect the master cylinder reservoir for the proper brake fluid level.
  2. Ignition OFF. Disconnect the brake fluid level switch connector. Measure the resistance between terminal A and terminal B of the brake fluid level switch. Verify that the resistance is greater than 75 k/Ohm.
    • If there is less than 75 k/Ohm between terminal A and terminal B of the brake fluid level switch when the master cylinder reservoir is full, replace the brake fluid level indicator switch.
  3. Remove all of the brake fluid from the master cylinder reservoir. Measure the resistance between terminal A and terminal B of the brake fluid level switch. Verify that the resistance is less than 25 ohms.
    • If there is greater than 25 ohms between terminal A and terminal B of the brake fluid level switch when the master cylinder reservoir is empty, replace the brake fluid level indicator switch.

Park Brake Switch 

  1. Ignition OFF. Release the park brake. Disconnect the park brake switch connector. Verify that continuity does not exist between terminal A of the park brake switch and ground.
    • If there is continuity between terminal A of the park brake switch and ground when the park brake is released, replace the parking brake indicator switch.
  2. Apply the park brake. Verify that continuity exists between terminal A of the park brake switch and ground.
    • If there is no continuity between terminal A of the park brake switch and ground when the park brake is applied, replace the parking brake indicator switch.