ATC System - Revised Diagnosis and Testing: Overview

Article No. 84-25-2

AIR CONDITIONING - VACUUM AUTOMATIC TEMPERATURE CONTROL SYSTEM - REVISED DIAGNOSIS AND TESTING PROCEDURES

FORD 1984-85 CROWN VICTORIA

LINCOLN-MERCURY 1984-85 GRAND MARQUIS, LINCOLN TOWN CAR

The following revised diagnosis and testing procedure has been devised to ensure a complete diagnosis of the vacuum ATC system. These procedures fully analyze the system for possible concerns and isolate individual ATC components for diagnosis. These procedures should also be followed when performing the predelivery check-out of the heating and cooling system. (These procedures can also be used on all present and past models with non-auto blower ATC systems by eliminating the auto blower procedure portions.)

DIAGNOSIS AND TESTING OF THE VACUUM AUTOMATIC TEMPERATURE CONTROL SYSTEM

Due to the complexity of all heating, ventilation and air conditioning functions in an Automatic Temperature Control system, it is important that the entire climate control system be checked when the complaint is not fully defined. Before verifying the complaint, a check of the following supporting systems should be performed.

^ Sufficient hot water to heater core
^ Proper operation of the refrigerant system (refer to Shop Manual Section 36-32)
^ Vacuum supply to vacuum reservoir (15 inches high or greater)

The diagnostics are divided into four sections. If the problem is not specifically defined, begin with Section I which is a general checkout procedure. Section I will then branch out to the other sections as the problem becomes defined.

The diagnostics are arranged as follows:

Section I. General Checkout Procedure to be used when the complaint is not fully defined or more than one problem exists. Also useful for pre-delivery checkout.

Section II. Complete System Response Diagnosis

Section III. Temperature Control Diagnosis

Section IV. Diagnosis for Individual ATC Components