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: Operation: Programmer: Notes
The programmer is attached to the HVAC module behind the glove box. It can be identified by the electrical and vacuum connectors attached to it.
The programmer contains circuits which accept data signals from the BCM, and provide controls for temperature regulation. The circuit board controls a small DC motor, which adjusts air-mix door position to blend cold and warm air. This motor is reversible and moves a rotary shaft connected to the air-mix door. The motor also provides air-mix door position feedback to the BCM.
These programmer circuits also respond to BCM data signals which operate 3 vacuum solenoids mounted within the programmer. These solenoids control the actuators, which in-turn operate the air inlet door, A/C-defrost door, and a 2-position actuator for the up-down door.
The programmer circuits also receive blower motor signal from the BCM, and transfer it to the power module for blower speed operation. These circuits also receive blower motor feedback signal, which is used to regulate actual blower voltage.
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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.