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.
Heater Control Valve Vacuum Switch
The heater control valve vacuum switch controls operation of the heater control valve. The heater control valve vacuum switch:
- is mounted on the RH side of the heater core and evaporator core housing just below the defrost door vacuum control motor.
- is actuated by an arm attached to the temperature blend door RH pivot shaft.
- applies vacuum to the heater control valve when the temperature blend door is in the full COOL position.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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.
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