wierd A/C /vent problem

[Dubb]

This is a little weird...curious if anyone has any ideas.

last summer, A/C is getting a little weak. took it to a shop, checked refrigerant, "topped it off" and put dye in. took it back a bit later and they found no leaks.

this summer, A/C starts only working when car is moving at a decent speed. sit idle, it would blow hot air....fan problem? yep...both died, and the mechanic had no idea how that could happen. $400 later, I've got two new fans...A/C is working OK...but only for a month or two. it's now back to only blowing cold when the car is moving, and even then it's fairly weak. every time I've checked the fans, they seem to both be working fine.

the other odd part: if you turn the A/C off, and put it as "vent" on the coolest setting, it blows hot air, even when moving. (provided the engine is warm). I would guess that the vent puts out anywhere from 20-40 deg. F above ambient temp.

could it be that the temp dial is tied to the computer, and that it's reading as "hot" even when I set the dial to "cool"?

the only other thing I can think of is that my engine is somehow putting out alot more heat than it should be...

eh?

 

[NutBucket]

Just a guess, but it sounds like the heater valve is stuck open or partially open.

 

[Sluggo]

Sounds like your blend door is screwed up

 

[Pacfanweb]

Auto climate control, or manual?

Could be a control head problem if auto, or blend door actuator if manual.

 

[Wolfie]

Another thing to check is between your raidiator and condenser. If it is plugged up, the exchanger can't work properly. I know that is an issue here in Minnesota when cotton wood trees crap all over the place and things get a little plugged. What happens when you put it on Heat? Could be a vacume leak on your blend door actuator.

 

[steppinthrax]

Sounds like a couple of things when you said every time you drive the car blows cold sounds like a weak compressor because when the car moves the accessory belt is spinning faster.

When you said it blows hot air even though the AC isn't on and it's on cold it sounds like the mixing flap that controls if air runs through your heater door is screwed up to a point where air is rushing through your core.