I own a 2004 XA, (stamped 01/04), w/84k, about a month ago my AC just started blowing warm air intermittently. I have tried to lock in when it happens but it is total random. Seams to want to blow warm air when the RPM drop but sometimes I can sit parked and it will run for as long as I can sit. Most of the time when it blows warm I can rev it and it will come on and blow ice cold again, then again i could be doing 70mph and it will blow warm, Temps are around 44-54 when cold, and as warm as 80 when acting up. Outside temp I think was 88-90 when testing.
I took it to a local AC shop; they tested the electric on the fan, the relay, and even toned out the power going to the compressor, Then Checked the gauges and immediately said compressor is bad. He wanted $1,800 to replace it and the dryer. I wanted a second opinion so I went to another AC shop and they said it's definitely not your compressor it has low pressure that stayed around 30ish but never fluctuated, High side around 170-I think, and fluctuated a bit, they said it appeared to be the expansion valve, something sticking in the small orifice in the valve. He wanted 600 for that and the dryer to be replaced. So my buddy does AC and we replaced both for around $60. Vacuumed it down and recharged the system. It does the same exact thing!! Is AC diagnostics this complex? I was reading through the forums and found someone having what sounded to be the same situation. They said if all electrical tests checked out to replace the AC amplifier ($114.97,Dealer part). I'm just wondering is this what others still think or could there be something else? And is there a way to test the AC amplifier??
Then to top it all off I called the local Toyota service center and explained my situation and he said it's my Thermistor sensor@$41.54, I saw where that was in the repair manual!! Right on the evaporator core!!! That looks like a bear to get to. The tech also said the new compressors do not switch on and off (so you will not hear the click sound) So far I’ve spent $60.00 on 2 evaluations, and $80.00 in parts. Maybe if I take it to Toyota they will give a definite description of the bad part and I can replace it myself. The heat is coming ARG...
Any thoughts are from the great peps out here?

 

AC confusion

 

Hey, I have the same problem, at highway speeds, it would cut off, now the A/C blows warm all the time. I have taken it to my trusted mechanic and he said compressor, and a friend who works on a lot of a vehicles said the compressor, or one of the connections could be bad to the compressor, like it got oil in it or dirt and is not making the connection, but he said 90% likely to be compressor. I am in the same situation and trying to figure out if fixing the compressor will fix the problem!

Also, mine is a 06 Xa, but if you change your compressor and it works, let me know! I am thinking about changing mine by myself, going underneath the car doesn't look that difficult to swap if you put it on some jack stands and pull of the skid pad, I just like you would like to know that it will fix the problem!

 

sounds like either a leak in the system somewhere, a sticking expansion valve (which op already replaced) or a bad low/high pressure sensor.