Initial Inspection and Diagnostic Overview

Automatic Temperature Control (ATC)

Due to the interactions of all heating, ventilation and air conditioning functions in an Automatic Temperature Control system, it is essential that the entire Climate Control system be checked to fully analyze the failure condition(s) and isolate the inoperative components(s) (Fig. 26). After a preliminary check to verity the concern, a check of the supporting Systems should be performed:

^ Heat to heater core

^ Air conditioning clutch operation

^ Air distribution for proper location and quantity

The following is divided into two parts. The first part contains a general checkout procedure to be used when the fault is not fully defined or more than one concern exists. The second part contains a detailed checkout procedure to isolate the condition to a component.

FIG.26: Refrigerant Lines: