Programmer Assembly

Programmer & vacuum harness:

The programmer, Fig. 4, contains temperature control components and is located on the right end of the heater and air conditioner assembly. The programmer can be identified by the electrical and vacuum connections attached to it. The programmer consists of a plastic case and components.

The circuit board is an amplifier and logic board that accepts electrical signals from the temperature sensors and mode push-button in the control head and provides output control signals. The circuit board transmits the blower control signal, the A/C compressor drive signal, the DC motor control signal which adjusts the air mix door position, and the regulated 8 volt signal which powers the control head and the power regulator. The potentiometer is adjustable for programmer calibration changes. A circuit board should only be repaired by a qualified technician with the proper service equipment.

The DC motor, located in the plastic programmer case, actuates the rotary shaft which drives the air mix door link, and is reversible.

Vacuum solenoids, inside the plastic programmer case, are actuated by signals originating within the circuit board. The solenoids control the vacuum to the vacuum actuators which control the hot water valve, the recirculating door, the mode door and the defroster door.