Automatic Temperature Control (ATC)

CIRCUIT OPERATION
Power for the ATC control head is supplied on circuit F20. This circuit is HOT in the RUN position only, and protected by a 10 Amp fuse located in cavity 6 of the junction block.

Power for the fuse is supplied on circuit A22 from the ignition switch. Circuit A2 from the Power Distribution Center (PDC) supplies power to the ignition switch. This circuit is protected by a 40 Amp fuse located in cavity J of the PDC.

Illumination for the control is supplied on circuit E2. This circuit is controlled by the Body Control Module (BCM) and the dimmer control.

Ground for the control is provided on two circuits. They are the Z1 and Z2 circuits. Both of these circuits terminate at the Airbag Control Module (ACM) bracket.

The BCM is used with this system to control the operation of the various mode door actuators, blower speed, and A/C operation. When the operator requests a function in the system, a message is sent across the CCD Bus to the BCM on circuits D1 and D2.

The BCM then processes this information and activates the proper function. It also sends a message back to the ATC control to illuminate the proper displays.