I just changed the heater core in my 1999 Subaru Legacy Outback. I had to take the dash out, and disconnect many connectors. After putting it all back together, my heat now works (yay!), but my AC no longer does.

Note that the AC worked (very) well before changing the heater core. I'm inclined to think that I missed a connector somewhere, but looked for hours and couldn't find anything. I checked the pressure on the AC system, just for good measure, and it's fine. The AC on/off switch inside the car lights up, but the system doesn't turn on. (The fans do work just fine though.)

Any idea what it could be, or where my missing connector might've been?

  • It is good practice to label all connector pairs BEFORE separating them - although knowledge, practice and experience tend to reduce the need... like knowin the meaning of the wiring colours so you know what the function is...
    – Solar Mike
    Aug 20, 2018 at 15:43
  • Yeah, I tried to take pictures of everything, but must've missed a couple. This would've been a good idea.
    – Cullub
    Aug 20, 2018 at 17:18
  • 2
    Subaru so most probably scroll/through vane fixed compressor. It should have an antifreeze temperature sensor in the evaporator case, maybe it's the one you forgot to connect back again. Also check for any wiring on the blower switch, some cars are designed to completely stop the compressor from engaging when blower is turned off.
    – Al_
    Aug 20, 2018 at 18:15


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