Hot air coming out of A/C when at a stop - Toyota Nation Forum : Toyota Car and Truck Forums

Jennyh · 07-07-2011, 06:11 PM

I've got a 1991 automatic 4dr Corolla. My A/C works fine as long as I'm moving. When I come to a stop at an intersection it starts blowing out warm then hot air. I've been told I need to replace the A/C solenoid. Can anyone tell me where I can locate this on my engine? I'm going to a junk yard to get a replacement.

SuperRA · 07-07-2011, 07:09 PM

Not sure what an AC solenoid is, but it sounds like the problem is a low charge of refrigerant. My cars started to do exactly that when they got low on refrigerant.

90 GP · 07-07-2011, 07:17 PM

The slower the engine speed the slower the compressor turns which lessens freon flow through system which in turn produces less cold air from the vents. Could also be a low charge as mentioned or your compressor may be weak form age. Get the system checked out to see if in spec.

Jennyh · 07-07-2011, 08:08 PM

The shop where I took it explained it as "what's happening at a stop is the solenoid that causes the compresssor to keep running even though the engine is idling is bad. If we replace the solenoid, it should keep producing cold air." Maybe they were using the term "solenoid" instead of another word, like switch or?? Is there some a/c carpart that keeps the compressor going regardless of engine speed and that's what needs replacing?

RogueMoog · 07-08-2011, 04:16 AM

Maybe they meant the compressor's clutch is bad? I don't know...

90 GP · 07-08-2011, 05:04 AM

What the shop is bringing up is a device that keeps the idle at the same speed it is with a/c off to compensate for the load the a/c puts on engine. There is an electronic switch on firewall with two vac lines that go to a vacuum bleed valve on back side passenger side of intake manifold. Check the vac lines for holes and make sure both are connected at both ends. It probably just needs adjusting. There is a large white plastic screw that you adjust to elevate the idle. You adjust it with a/c on. If your car has a tach check idle speed with a/c off and adjust switch with a/c on to get same reading.Do it with car in drive (with handbrake set) foot on brake and get a helper to make the adjustment under the hood. It's any easy fix . Just did it on my car last week.

Jennyh · 07-08-2011, 04:43 PM

Wow. Thank you for that detail. It's always interesting to get underneath the car and look at stuff...