Electronic Replacement of Vacuum Controls in Automotive Climate Control Systems

This paper discusses an electronically controlled, electric servo control system for air conditioning and heater controls which is independent of vacuum, and engine operation. This new system uses electric motor driven actuators to position mode valves and the air blend valve through a microprocessor in the control panel.

The microprocessor is preprogrammed to automatically regulate system operation and blower speeds. It also provides the capability to analyze actuator positions and wiring, and provides a positive go-no-go visual diagnostic signal if service is required.

Introduction of electronics into the system provides capability of infinitely variable blower speed control, touch operation, and for additional unique performance features not possible with mechanical systems.