any help on a/c problem? my truck blows cold air only when idle. when I slightly apply the gas pedal, I hear (what sounds like) something closing in the dash area and immediatly starts blowing warm air.I turn switch to off,then back off the throtle and switch back to a/c,then cold air blows until I accelerate again.any knowledgable info is greatly appreciated !!! thanx...JL

 

What year is your truck? Most vehicle turn a/c off under WOT (wide open throttle). Maybe some thing there but I'm guess low freon.

 

You need to verify if the compressor clutch is cycling off or if the vents are closing off. If the compressor is constantly kicking in and out, every few seconds, then youre low on freon. If the vents are just closing, then you have a vacuum leak somewhere in the system.

 

Sounds like you have a vacum reserve canister problem wheather it be the canister is not holding vacum, the one way valve isnt holding or the vacum lines themselves are leaking.Also you may have a AC controler(AC control switches) leaking excessive amout of vacum which will cause this problem also.

Good luck and lets us know what happens

 

Hey, good point on the vacuum

 

Hey gentlmen, thanx to all of you for reply !!!!!!! I will be checking all your tips this wknd. THANX AGAIN!!!J.L.

 

Well I removed vacume resevoir box and re connected the two lines together.SAME,SAME WITH NO CHANGE AT ALL! hOW DO i TEST FOR VACUME LEAK AND WHERE TO LOOK,TEST AND FIND ALL THE AC VACUME LINES ETC?i GUESS i NEED A GOOD LEGIBLE DIAGRAM FROM ? SOURCE? I WOULD CHECK TJE AIR CONTROL SWITCH BUT I DO NOT KNOW HOW TO BEGIN OR WHAT TOOL TO USE?

THANX GUYS !!!!!!

JEFF

 

It is the vacuum cannister check valve, usually a black plastic thingy inline with the hose going from the engine and the cannister.
It is no longer a check valve, its stuck open both directions allowing it to lose vacuum whenever supply drops(throttle open).
Its not the WOT switch.