Quote:
Originally Posted by rpm5099
You are dead on the problem. Whether the problem is A or B, the fix is the same. Put a 20kohm resistor on that thermistor clip. The measurements aren't that important, it's the same incorrect Toyota part inaccurate by the same resistance differential all of them are. If you are worried about cutting wires you can stick the resistor prongs in the wiring harness and tape it temporarily (make sure it has contact). The only reason to not leave the circuit jumpered is to avoid icing up, especially in cold weather with defrost on.
It doesn't really matter how much contact the thermocouple has with the evap coil surface, they are very sensitive. If it's in the evap housing and in front of the air discharge it's fine.
I am pretty much 100% certain this will fix your problem based on what you've said.
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Hey man! Incredibly late reply, but I ended up testing your theory pretty significantly with my AC system in my '03. I started using a 20k ohm resistor on mine, and it was good for an extra 5 degrees pretty much all the time.
Turns out, my compressor starting going bad due to a bad clutch (it was the original compressor, 21 years old). So I just had that swapped out, and I took the resistor out beforehand. When I got it back, I was cycling between 49-56 degrees at idle (70 degrees outside temp). With the resistor back in place, I'm down to 44-50 degrees at idle. This is pretty much dead on with my fiancee's Ford Escape which has great AC (by our standards at least).
So in my case, it definitely made a difference. And so far, I haven't seen any temps low enough to cause a freezing situation inside the evaporator. That 20k ohm seemed spot on. We get a lot of humidity near the coast so I'll do some further testing as summer rolls in.
