Brake Switch (Cruise Control): Testing and Inspection

1996 Oldsmobile Eighty-Eight LSS FWD V6-3.8L VIN KSECTION Testing and Inspection
1. Turn ignition switch On, then turn cruise control switch On.
2. Install Tech 1 scan tool.
3. View C/C brake switch. Scan tool should indicate RELEASED and switch to APPLIED when brake pedal is depressed.
4. If brake switch status is incorrect, probe CKT 397 with a test light to ground. If test light does not light, refer to "Testing and Inspection."
5. If test light does turn on, connect jumper between CKT 397 (GRY) and 86 (BRN) wires on brake switch. If Tech 1 display switches from RELEASED to APPLIED as the two wires are connected, adjust or replace brake switch as required.
6. If switch status does not change when the jumper is connected, then CKT 86 (BRN) wire is open or shorted between the brake switch and PCM. There may also be a poor connection at the PCM or a faulty PCM.
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.