Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSCHEVROLET1987HI-CUBE 6.2 J, 475/M40REPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 45 (DIAGNOSIS - A/T)SERVICE BULLETINSBRAKE SWITCH TEST
1987 Chevrolet Hi-Cube 6.2 J, 475/M40
Brake Switch Test
1987 Chevrolet Hi-Cube 6.2 J, 475/M40SECTION Brake Switch Test
WARNING: This page does not describe the selected car, but rather 138 other vehicles, including the 1992 Saturn SL2, 1992 Saturn SL1, 1992 Saturn SL, 1992 Saturn SC, and 1992 Pontiac Trans Sport. However, it is still accessible from the selected car via links, so may be relevant.
- Ensure fuse marked "gauges" is okay (most models). Check for 12 volts at both sides of brake switch(es). Some GM vehicles have 2 electric switches at brake pedal. One switch will have 4 wires and the other switch will have 2 wires and a vacuum hose.NOTE: Either of these switches can be used for lock-up. To avoid misdiagnosis, check both switches. If upper switch with vacuum hose is used, check 2 wires at that switch. On 4-wire lower switch, check 2 wires farthest from plunger.
- Ground test light. DO NOT depress brake pedal. Turn ignition on. Check wires for voltage. Voltage should be present at both wires. Depress brake pedal and retest. Only one wire should have voltage.
- If brake switch did not pass previous test, remove brake switch and repeat step 2), pushing and releasing brake switch plunger. If brake switch fails test, replace switch. If brake switch is okay, adjust switch as necessary.
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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.