AC worked great for a long time...then my blower motor went out...so I replaced that..everything worked fine again...then my AC control **** started getting harder to switch to the different settings (OFF, MAX, NORMAL, etc)......the fan speed one still worked fine though...then the settings **** got more and more harder...and i started noticing a very slight hissing sound coming from the controls....if I slightly moved the settings ****, the hissing would go away...whenever I turned it off...the hissing would continue...Id have to turn it on and back off to make it stop. Then my AC started acting even more weird....one day I went out for a drive...turned the car on..turned the AC on....it idled normally.....everything was fine...it then started to idle very strangely...first it would idle really high....then really really low...almost to where it was about to die...then really high...then really low. I opened the hood...and noticed that my AC clutch would turn on and off about every 10 seconds....for about 5 minutes straight....and everytime the AC would engage...thats when my car would idle really low and almost die...when the clutch disengaged...it would go way up. Then....after a few days...my ac clutch stopped engaging and disengaging all together....and none of the controls on AC switch would work. I would go through every single setting....all all temps and fan speeds...but the blow motor wouldnt turn on...and there was absolutely no cold air coming through the vents....not even the heater worked....there was still a slight hissing sound though. Then a few days later...the hissing sound went away....nothing worked. Then that last time it iced over here...i had to go to work and my windows were iced over BAD....i went to turn on the defroster forgetting the controls didnt do anything....and of course it didnt work....i then was switching it back off...and the MAX AC started blowing...so I switch it over to defrost really quick...and it stopped working...and the AC didnt work anymore either.....and from then on it hasnt worked at all. So I took the AC/heater controls out, looked at it...everything was connected...the vaccum lines look pretty good......I also noticed (since it was pretty quite) then whenever i turned "on" the AC...the radiator fan would quick on like it should. So I took the controls all apart....and messed with it a bit....the air/heater control (i believe its called...the disk lookign thing on the top) was a bit flimsy..but it turned the radiator fan on......one thing about that though...I would turn it with my hand all through its settings..and nothing would happen...and it would get stuck on its stop....but then I would force it past the stop...and the defroster would kick on....so that means the blower motor IS still good.....I put the switch back on..and i noticed that when I put it on the defroster setting using the ****...it would stop right at the stop that I previously forced it past.....So anyways...sorry about the long message...but....I called Partzone Online...and ordered a new ac/heater control.....the guy i was talking to said it may be the little round valve that the main vacuum lines plug in to...and he could sell me the individual parts that I needed....I told him to just forget it and I would replace the entire thing and be done with it...for $60 its not bad. So now its shipping to me...but my question is....is this REALLY what the problem is?

Oh and one thing I forgot to mention...my manager at worked told me it may be the pressure switch that is on the side of the accumulator...we changed it out with a new one just for kicks...and the defroster would start blowing....put the old one in...the defroster wouldnt blow at all.....new one in...would blow. He also said that when he screwed the thing in...freon should have started coming out when the pin was pressed...and it didnt...he pressed the pin in by hand and a little puff of freon came out...and thats it....so I have no freon whatsoever....could that hissing I was hearing be the freon that was leaking out even though im pretty sure its coming right from the controls.....either way....I dont care about the ac right now....I just want the heater and defroster to work....Im gonna be getting a new compressor and everything later...and convert to R134a....so I dont want to spend the money on refilling with R12....will just hold myself over for now with the tops off and the windows down.

Again i apologize for the long post.

 

??

 

mmmmmmm AC, taste like chicken

 

Mult,

You have a couple of problems. The HVAC control getting difficult to operate is probably caused by the ported vacuum selector in the dash controls getting dried out after however many years the car is old. The ported switch is bazically a labyrinth of passages in two halves that rotate against each other to direct vacuum to the correct port in anay given selector position. These two halves are sealed by heavy silicone grease, and this grease can dry out or get displaced after years of use. The only remedy for this is to remove the controls and clean/regrease the ported switch. I've done this before and it isn't difficult, just time consuming.

As for the rapid cycling of the AC compressor, you need to get a set of gauges on the system to verify this, but it sounds like you lost your refrigerant charge. You can leak test the system with propane instead of refilling it with R-12, then evacuate the propane once the leak(s) is repaired. This is a lot more cost-effective than using the $18.00/lb. refrigerant as a leak test.

 

My A/C system is doing the same thing. I haven't had a chance to look at the switch yet, but what type of grease would be used on the switch?