Initial Inspection and Diagnostic Overview

Operation of the A/C clutch is dependent on the ambient temperature and signals from the Powertrain Control Module (PCM). Strategies are programmed into the PCM to interrupt A/C clutch operation when certain conditions exist. The A/C clutch can be shut off (or kept off) for several seconds at engine start-up, during high engine speeds, during acceleration, when the engine coolant temperature exceeds a predetermined temperature, and during low engine idle conditions (approximately 200 rpm below low idle specifications).

It is often possible to detect concerns by a careful visual inspection of the A/C refrigerant system. This includes broken drive belts, obstructed A/C condenser core air passages, excessive A/C clutch air gap, loose or broken mounting brackets, disconnected or broken wires, and refrigerant leaks.

A refrigerant leak usually appears as an oily residue at the leakage point in the system. The oily residue soon picks up dust or dirt particles from the surrounding air and appears greasy. Through time, this will build up and appear to be a heavy, dirt-impregnated grease.

Most common leaks are caused by damaged or missing 0-ring seals at the various hose and component connections. When these 0-ring seals are replaced, the new 0-ring seals should be lubricated with silicone or refrigerant oil. Care should be taken to keep lint from shop towels or cloths from contaminating the internal surfaces of the connection. Leakage may occur at a spring lock coupling if the wrong 0-ring seals are used at the coupling. Use only the green 0-ring seals listed in the Ford Master Parts Catalog for the spring lock coupling.

Missing A/C charging valve caps (19D702) can also cause a refrigerant leak. If this important primary seal (the A/C charging valve cap) is missing, dirt enters the area of the A/C charging port seal. When the service hose is attached, the valve depressor in the end of the service hose forces the dirt into the A/C charging port seal seat area and the dirt destroys the sealing surface of the port seal. When an A/C charging valve cap is missing, the protected area of the A/C charging port seal should be cleaned and a new A/C charging valve cap should be installed.

CAUTION: A/C charging valve caps must be installed finger-tight. If tightened with pliers, the sealing surface of the A/C charging valve core may be damaged.

Test equipment must be connected to the refrigerant system in order to make system tests. If a charging station is used, follow the instructions of the station manufacturer.