So, I got the A/C working last week.
I went out to the Subaru junkyard and got an ECM for $80. Plugged it in, and the A/C works... for about 20 minutes. Then the check-engine lights comes on and we're right back where we started.
So I did some more googling, specifically the check engine and flashing cruise control light. Turns out there is a 'boot up' sequence you must undertake any time you have the battery disconnect for any extended length of time. Basically you disconnect the battery, and leave the key 'on' for 20 minutes or so until every last electron is out of the system. Then you connect the battery, start it up, but don't touch
anything for 20 minutes - just let it idle and let the ECM re-learn how to run the engine. This worked. The A/C worked again, and
stayed working.
I went back to the shop the next week and explained my process for fixing the car. He was impressed, and refused to charge me for the work he'd already done - the A/C evac, re-charge, and replacing the pressure switch.
The wife is in love with her new X3; does anyone want to buy a nice Saabaru?
