Component Functions: Programmer

The programmer is attached to the HVAC module behind the glove box. It can easily be identified by the electrical and vacuum connectors attached to it. Contained within the programmer are circuits which accept data signals from the BCM and, in response, provide the controls for temperature regulation. The circuit board controls a small DC motor that adjusts the 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 4 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 a blower motor signal from the BCM, which it transfers to the power module for blower speed operation. These circuits also receive a blower motor feedback signal, which is used to regulate actual blower voltage or speed.

The programmer also provides control for the rear window defogger. When the programmer receives the rear defogger signal, it provides the ground to activate the rear defogger relay.