Ford A/C :: 2006 - Air Condition Went Out / Compressor Turns On Runs For A Few Seconds And Then Turns Off

I have a 2006 Expedition with 90k miles. I am the original owner. don't drive the vehicle much just mostly when the family goes somewhere or when I'm putting the Jet skis in the lake.

About a year ago the air con went out and since I don't drive it that much I decided to fix it later, well now is later. How to diagnose the AC system. what I am looking for is a methodical step by step procedure for trying to find out what is causing my AC to not work.

the symptoms are, the compressor turns on runs for a few seconds and then turns off. inside the cab I can hear hear a hiss noise during the few seconds that the compressor comes on and fades away slowly when the compressor shuts off.

I bought a can of 134a with the gauge, I adjusted the gauge for the correct ambient temperature hooked up to the low side and was surprised to see that the Freon was only a little low. I topped it off but still no change in the compressor running.

I bought a set of manifold gauges from Harbor Freight (I know I know you get what you pay for) in any case I hooked up the gauges to see what the pressures are when the compressor turns on but only seeing a little change.

Any way I took my Speedy (expedition) to the local auto air conditioner shop the mechanic hooked his gauge set up to the vehicle, watched it for a few minutes, made some phone calls, came back. He did tell me that he was going to have to replace the compressor, condenser, dryer, expansion valves both front and back and flush the rest of the parts that did not get replaced. I suppose this is a good price if all that work really needs to be done???

However I would like to exhaust all of my options before I dump half the vehicles blue book value into the air conditioning. so I've been searching the internet and found that it is possible the problem may reside in a control valve that may be present in the type of scroll compressor that is in the expedition.