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.
Temperature Control Lock-Out Valve & Switch
The temperature control lock-out valve and switch is a combination vacuum valve and single-pole, single-throw switch. Switch is located on heater inlet hose in engine compartment. See Fig 1 . The thermal element of switch contacts coolant.
When function lever is in FLOOR position and engine is cold, blower cannot operate and outside/recirculated air door is held in recirculation position. When coolant temperature reaches about 120°F (49°C), electrical switch contacts close, allowing blower operation and outside/recirculated air door to move to outside air position.
NO RELATED
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.