Programmer Assembly

The programmer is attached to the A/C module assembly behind the glove box within the passenger compartment's instrument panel. The programmer contains a small 8 volt DC motor and variable resistor (potentiometer) with an air mix (temperature) valve position feedback center tap, four vacuum solenoids and electronic switching amplifiers and drivers mounted on a printed circuit board.

Three logic input drive signals derived by the controller determine the air flow position of each valve controlled by one of the four solenoids. The programmer accepts these low current command signals initiated by operator selected mode key pad switch positions and two temperature sensor readings. The programmer then energizes specified solenoids by grounding one side of the solenoid through the designated electronic switch. Vacuum is then applied to the selected vacuum motor actuators which reposition any one, two or all three valves to control air flow in the A/C module.