cfuller74

My A/C works fine 90% of the time. Ice cold air and system recharged earlier this year. It's the other 10% of the time that's irritating and very annoying!

Ok, so this is the pattern of behavier:

Morning: Car leaves house garage. Ice Cold A/C out of the vents

Afternoon: Car leaves work parking garage. Ice Cold A/C out of the vents

After lunch (annoying time): Car has been sitting in sun an hour. Nothing but warm air out of the vents! By the time I get back to work (10 min drive) A/C never blows cold air

After work: Car leaves work parking garage. Ice Cold A/C out of the vents

After gym: Car has been sitting in sun for about an hour. Trip home and Ice Cold A/C out of the vents. WTF?

So it was very hard to "search" for this intermittent symptom. Seems to only act up on the way back from lunch. Annoying and embarrasing!

I have a 98 Gs400 90k miles and everything else seems to be fine. I'm thinking it may be some kind of sensor issue?? Why does it decide to blow Cold Air after my gym trips even if the car has been in the sun? Strange problem...

Any ideas?

Thanks!

Spyder78

iTrader: (7)

when the car starts to blow hot air does the ac light on the button start flashing? If so than the ac compressor is not engaging I have a similar problem and my issue is that the ac clutch is not holding so I need to get it replaced, only happens sometimes.

LexusPia

Take it to an outfit that specializes in cooling and AC. I believe your problem stems from a defective thermal switch and possibly the dryer unit. When the engine is cold or park in the garage, the AC works fine but after you run it for awhile or park it under the sun, a bunch of hot air comes out. I had the same problem you described in my '94 ES3 that the cold air would work intermittently. Lexus dealer said my whole AC unit including compressor was shot and they said it would cost me about $1500 to 2000 depending on what they could find. Being somewhat mechanical minded, I told the dealer that was impossible since I would not be getting any cold air at all if the compressor was shot. I took it to a local store that specializes in AC and cooling, they found the problem as described above and fixed it for about $278 including new freon. It's been working like a charm since. If your car is out of warranty, don't bother taking it to a Lexus dealer unless you got money to burn.

cfuller74

Hmmm.. The ac button doesnt' start flashing. However, it does sound exactly like the post above! :-)

cfuller74

That sounds like it!! I'll definitley avoid taking it to a dealer in this case. Thanks a lot for the advice!

Hectorm

Similar problem in all Toyotas. Looks like is a defective relay which I can't tell you which one is bad, so look under the hood and check the relays panel and try to swap similar rating relays.
Other way is to visit an A/C tech. They know foe sure how to diag. your problem.