Super weird Yaris 2003 A/C problem

[CoryM]

Originally Posted by zoharby

Compressor is still getting power (they put a LED on the line which stayed on).

Assuming that is true, you know it's not a control problem or electrical issue. So long as the compressor has power and ground and the clutch is locking, your a/c should be blowing cold. I would suggest the next step is to hook up the refrigerant pressure gauges and induce the problem. If you see the low pressure side going from normal PSI to vacuum and back, it's probably a blocked orifice. If your pressures are normal until it acts up, it's probably ice. Your dryer could be saturated with water, and/or the refrigerant is contaminated with water. This is my guess from thousands of miles away. If it is, replace the dryer and use NEW refrigerant.

With pressure gauges you can diagnose just about any pressure related issue. It's been too long since I did that stuff to remember it all.
Here is a chart that may be handy.

http://www.sanden.com/objects/SANDEN...OSIS_CHART.pdf

Cheers.