Re: AU a/c prob - PLEASE HELP!!!
It sounds like the A/C is overheating. They have a thermal switch. Here are some things to check, they may not apply to your car but do apply to car A/C in general.
1. I assume the FORD service, have regassed your A/C ? This is number one reason for this happening!!
2. After the A/C has been going a few minutes note the temperature of the hose/metal pipe going to the radiator from the A/C. (Approx. temp is OK. i.e. the hose is damn hot; the hose is luke warm! etc)
3. Find the hose that goes from the radiator back to the A/C unit, check that this hose is COOLER than the temperature of the hose going to the radiator.
4. When the fault first occurs recheck the temperature of the hoses. If the hose that was cooler is much hotter then your problem is at the radiator.
5. Check that the fan on the radiator kicks in. If not you have a faulty fan temp sensor on the A/C side.
6. Check that the fan rotates round smoothly - ONLY DO THIS WHEN THE ENGINE IS COLD - fans can turn on even with the ignition off if a temp. sensor cuts in!! If it doesn't then the fan bearings/unit needs replacing.
7. The blocked water tube from the A/C, as mentioned by another poster, is also a good candidate for this sort of problem.
8. Check the wiring to the A/C. i.e. undo the elec. plug and clean the pins/socket.
9. When the A/C is known to be working, turn off the engine, disconnect the A/C plug, turn the engine back on, check the voltages at the socket. Turn off engine. Connect plugs/socket back up. Run until A/C fails. Turn off engine. Disconnect plug. Check voltages are the same. (This will tell you whether the problem is with electrical feed).
10. A magnetic clutch or similar is used to engage the A/C unit with the driving fan-belt. With no power, the A/C pulley on the driving fan belt is freewheeling - it is not connected to the main spindle on the A/C. With power the A/C pulley is physically locked together with the A/C spindle. You could have a problem with the magnetic clutch failing electrically. i.e. the windings get hot, and a loose connection is broken, windings cool down and the connection is made again. But I would have thought arcing would soon stop it from working at all.