ponyex02

I have a 1995 Mustang GT. The problem I am having is the AC will work just fine it gets good cold air and the compressor and fan shuts down and the car overheats. Everything on the AC is new. Except for the cooling fan.

mjr46

if car is overheating, you need to address that/resolve that issue first as when temp gets to hot ecm and or ccrm may not allow compressor operation

ponyex02

The car over heats after the compressor and fan shuts down. You can drive the car for an hour and it does fine good cold air then you feel warm air and the compressor and fan shuts off then car over heats.

Derf00

1) Check coolant level
2) do a pressure test on your cooling system
3) if both of those are fine could be a blockage in the cooling system

If you system is a single fan then your fan is fine. If it's a dual fan system, one is for A/C, the other is for cooling. Check the cooling one. Could be the motor or could be the temperature switch for the fan.

lxman1

The ECM will shut down the a/c when the coolant temp reaches a predetermined temp. Around 235-240.

Possibly either a clogged radiator or sticking thermostat.

ponyex02

The cooling system checks out. Has a new radiator, new thermostat, new temp sensor have by passed it before and it makes no difference. Replaced two CCRM boxes. It appears to be some kind of electrical problem because when this happens the compressor and the cooling fan both shut down.

lxman1

Recheck all of the under hood grounds. Especially the engine to chassis straps.
I would also inspect the actual ignition switch under the column. They are notorious for coming loose and getting a bad connection which can cause a lot of weird issues. The white plastic part should be real tight in the metal housing. If it is loose, you can sometimes save them by tapping the 4 metal tabs that hold the plastic part with a screwdriver and hammer to tighten it up.
May or may not be the case, but worth looking into.

Does the a/c clutch have a separate relay like a FOX body or is in in the CCRM box with the fan relays? It could also be a bad connection or switch on the HVAC controls, but that should only kill the compressor and not the low speed fan for engine cooling, unless it is set up to bypass low speed when the a/c is on.
Hard to diagnose without being able to see the car act up in person.