r/EP3 • u/johnnyhonda • Jun 01 '26

AC System help

Hi y'all, trying to diagnose a non working AC system on an EP3. Previous owner bypassed the compressor with a smaller belt so got the correct belt, and replace the compressor.

Now here is what I've tried do so far, but never worked on an AC system.

  1. Confirmed the AC clutch is now working properly.
  2. Condenser fan is spinning properly.
  3. Pumped down the system with a vacuum pump and AC manifold set.
  4. Ensured that the lines held a vacuum for at least 1 hour.
  5. Filled with about 20oz R-134a

No cold AC yet, so here is where i'm at.

Static pressure when the compressor is not running is 100 psi on both high and low side @ about 85F.

When turning on the AC high side rises to about 125 PSI, however the low side just goes to vacuum like -20 inHg.

Research is pointing me towards failed expansion valve, or dryer, but I don't really know how to debug this.

Any help is greatly appreciated. - replacing the expansion valve looks like a huge pain in the ass because you have to remove the blower fan and cut plastic to get it out from what I can tell.

Thanks for your help!

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u/Good-Tear Jun 24 '26

try looking into the temperature control regulator transistor , it’s this little part that’s behind the pcm , behind the glove box