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.
A/C-Heater System - Automatic (Fwd): Operation: Programmer
The plastic programmer case contains temperature control components. It is mounted on the right end of the A/C-heater assembly. The amplifier and logic board are a combined unit.
Programmer accepts electrical signals from both the sensors and mode push buttons in the control head, and also provides output control signals. A reversible DC motor, located inside programmer, actuates a rotary shaft to drive the air-mix door link.
Signals from the circuit board actuate the vacuum solenoids within the programmer. These solenoids control the heater control valve, air door, mode door and defroster door.
NO RELATED
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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.