a/c vacumm trouble

2000 e150 when I accelerate the a/c shuts off. Is this a vacuum or check valve problem and where is the check valve?
John

I wish I knew. But mine does not shut off. It goes up to the defrost vent, still cool. Only does this when driving. any ideas???

I just went thru this on my 1994 E-150. You have a vacuum leak. It could be one of the small rubber lines going to distributer, EGR valve, vacuum reservoir, etc. You have a check valve that could be bad, it's usually on the line going to the reservoir or may be part of it. You have hoses originating behind you climate control panel that feed multiple vacuum motors. You should get a hand operated vacuum pump and the vacuum diagram for your van and isolate and test each line. Goes faster than it sounds. Harbor Freight has a pump kit for $25

I've had the main vacuum connection at the intake plug I had to remove the fitting and clean out with a small screwdriver and wire.