They were probably talking about the compressor relay. It is part of the "constant control relay module" (CCRM) The module also contains the relays for the fuel pump, cooling fans, A/C clutch and the PCM. It is behind the coolant reservoir.
There are a couple other items that should be tested as well, the high and low pressure switches can fail and either one will prevent the system from working. They can both be tested or replaced without needing to discharge the system.
The low pressure switch(aka cycling switch) opens if the pressure in the system drops below 22-27 psi and closes at around 35-40 psi. So if it is tested while it is installed it should test for continuity if the system has R134A in it.
The high pressure switch is tested the same way, it should be closed until the system sees a high pressure. Setting still and the clutch not working it will be closed.
So if there is correct R134A amount in the system both switches should be closed.
Easy way to test, unplug them one at a time and jump the two wires, turn on the AC, if it works with either one jumped then the switch is bad.
Those switches are either on the accumulator or in the lines, Ford used a couple locations depending on actual build date.
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Wednesday, November 22nd, 2017 AT 11:57 AM
