i had many A/C issues but firestone could not seem to diagnose. Then one day, my ac started working fine again. Well, now my ac gets warm if i keep the fan low or at medium. So, i now keep it at high. Now, when it is at high, if i suddenly turn it off, and turn it on again, the compressor doesnt come one. One the compressor turns off, i have to keep the a/c off and wait to hear for a hissing noise from the vents before i know i can turn it on again. Does this sound like anything particular?
Chris

 

Are you Low on Freon?
Does the cooling fan under the Hood work?
When the compressor won't come on do you have power at the Low pressure switch and Compressor?

 

The air does blow pretty strong, and the fan right behind the front grill does work(I hope thats the fan you were speaking of)

 

Yes that was the Fan I was talking about.
Do you have power at the places I spoke of above?

 

Hey how are ya first post on this site I just registered looking for some information on Volvo cars. I'm thinking of buying a Volvo car as a second car, for some reason my sports car and motorcycle are a bit impractical for a lot of my comuting needs! I must be growing up haha

Well I say an A/C post on top when i first looked into this site so i thought i may be a bit of help with this one, I'll be looking for some advise late so it's the least i can do!

Where you say there is a difference of operation between different insice fan speeds don't make a lot of sense, all i can think of what's going on is when the fan is slower the load on the evaporator coil in the airbox is lower there fore the pressure is lower, if there's a shortage of refrigerant(freon) maybe that pressure is getting too low and locking out the compressor.

when you turn off the compressor and there's a hissing sound then it works possibly that could be the high and low pressure sides of the system equalizing pressure when it's off and when it equalizes the pressure increased on the lowside sensor allowing the compressor to be activated again

once it is working and on 'high' does it work for a long time or does it only last a little while?

There's something wierd going on here you'll need to look at the pressures with a gauge and see where the cut in and cut out points of the comptessor are taking place and also you should take some temperatures of the refrigerant lines and the coil temperature

-Mike

 

When the a/c is on high, it will stay very cold forever, or until i am at my destination. it is when it is on med, is where the problem occurs. On low, or medium it will stay cold for about 5 minutes, then get foggy and then warm. now, i was recently on an hour trip to the beach. i had it on high for like a half hour and it was blowing nice and cold. i turned the ac off and on instantly and it got warm and would not get cold again. that was weird, since i clicked it on and off instantly. oh well, i hope this is somewhat making sense.

 

But like I said above you need to find out where you have power when it isn't working.