Low-Charge Protection Switch

WARNING: This page is about a different car, the 2005 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.

The low-charge protection switch (19E561) is used to prevent A/C compressor damage in the event of a low refrigerant charge.

The electrical switch contacts open when the suction pressure drops below normal levels. The contacts close when the suction pressure rises. For specifications regarding operating pressure(s), refer to CLIMATE CONTROL SYSTEM-GENERAL INFORMATION .
When the low-charge protection switch contacts open, the A/C clutch field coil is de-energized and compressor operation stops.
The low-charge protection switch is mounted on a Schrader valve-type fitting on the top of the suction accumulator/drier.
A valve depressor, located inside the threaded end of the low-charge protection switch, presses in on the Schrader valve stem, allowing the suction pressure inside the suction accumulator/drier to control the operation of the low-charge protection switch.
It is not necessary to discharge the refrigerant system to remove the low-charge protection switch.

Fig 1: Exploded View Of Spring Lock Coupling Components

Courtesy of FORD MOTOR CO.

The spring lock coupling is a refrigerant line coupling held together by a garter spring inside a circular cage.

When the coupling is connected together, the flared end of the female fitting slips behind the garter spring inside the cage of the male fitting.
The garter spring and cage then prevent the flared end of the female fitting from pulling out of the cage.
Use only the O-ring seals listed in the Ford Master Parts Catalog for the spring lock coupling.
A plastic indicator ring is used on the spring lock couplings of the A/C evaporator core to indicate, during vehicle assembly, that the coupling is connected. Once the coupling is connected, the indicator ring is no longer necessary but will remain captive by the coupling near the cage opening.
The indicator ring may also be used during service operations to indicate connection of the coupling.
An A/C tube lock coupling clip may be used to secure the coupling but is not required.