ancdmd

Starting a few months ago my a/c has not been working correctly, it takes anywhere from a few to ten minutes to blow cold air. It just blows hot air and then all of a sudden switches to cold. And NO, it is not just because "its hot out and it takes a while for the air to get cold". Normally, regardless of how hot it is outside, the a/c will start blowing cold air almost immediately, there is little to no delay in getting cold air to come out the vents.

This problem first started back in May on a hot day when my car was sitting out in the sun all day at work. Over time the problem has become more frequent, and it seems to be related to underhood ambient air temperatures. Sometimes it'll take ten minutes for the air to kick in and I'll drive for a while, park and leave the car for five minutes, then restart the car and the air won't blow cold again for another ten minutes. Today, I could not get any cold air to come out at all, no matter how long I drove. It was in the low 90's today here in South Florida.

I had the mechanic check it last week and he said it was operating fine (it was blowing cold air at the time) and he couldn't find anything wrong with it. Figures.

Any ideas?

V8_Fan

I had something like this happen on my old Toyota truck. Turns out the A/C amplifier was bad (it would intermittently be cold or hot).

ancdmd

what is an a/c amplifier?

fuz16

iTrader: (5)

My car did this. It was the fan motor on the passenger side of the cooling fans by the radiator. When the car is sitting still the fan would not turn - therefore no cold air when parked or at a red light, but as soon as the fNs were turned by air passing through them when driving the air would become cold again. I had to replace the fan motor and it solved the problem. Good luck.

ancdmd

In my situation even when I'm driving I'm not getting cold air. It has nothing to do with the speed of the car. It seems like it might be an electrical problem, as if the compressor is not being activated or something.

Jabberwock

Some things to check:

The fans have to be running for the AC to work. Check to see if the electric fans are turning when its not blowing cold and you have the air on. Maybe a fan relay is sticking.

If the fans are turning when its not blowing cold check to see if the compressor is turning. The inside hub on the compressor should be spinning. To see what it is supposed to look like have someone turn AC on and off (when its actually ) blowing cold and you should see the compressor hub stop and start spinning.



So if the fans and compressor are running correctly when you have AC on then check this stuff:

When its not blowing cold try shutting system completely off and then starting it up in non auto mode - change anything?

Also try cycling thru some of the settings when its not blowing cold:
Does it kick in if you switch to manual versus auto mode?
Does it kick in in if you run temp up to 90 and then immediately back down to 68 (maybe bad/flaky temp control)?
Does it kick in if you switch between interior or exterior vent (stuck exterior vent door)?
Does it kick in if you switch to defrost instead of standard center or floor vents (maybe stuck door)?

Check cabin air filter - unlikely but take a look and also inspect inside filter housing with flashlight and see if anything looks jammed, obstructed or broken with housing or interior fan.

Kansas

Did your mechanic hook up his gauges and determine whether the refrigerant level is within specification? The refrigerant level can look just fine based on the sight window but can still be low enough to make the A/C system work erratically.

Slow leaks can be hard to find. My mechanic tried unsuccessfully to find a refrigerant leak in my 00 LS in summer 2008 by the usual method of putting dye into the system. It took almost another two years before the dryer canister leaked enough to become obvious.

Before the dryer canister and fittings were replaced earlier this summer, the A/C would sometimes work great and other times hardly at all on the same day. I'm not saying your problem is the dryer but that your refrigerant level could be just low enough for the A/C system controller to become "confused".

ancdmd

The system was low on refrigerant over a year ago and my mechanic did add coolant then. The sight glass still looks the same, no bubbles, and I believe all my mechanic did was look at that sight glass and assume it was full. Next time I take it in I'll make sure they do all the diagnostic stuff needed to find the problem.

V8_Fan

If it were a fan clutch, you would still feel cold A/C when the car is moving (like 30mph or faster), but it would turn warm when the vehicle came to a stoplight. You might also see the engine temperature increase at the stoplight.