Ok I've searched and read dozens of threads, but I'm still confused. Why does the A/C sometimes work and sometimes doesn't? I couldn't tell from what I read ... is there a particular year or VIN range etc of cars that do and don't have the A/C problem once the PFC is installed?? I guess what I'm getting at is that rather than doing the "mod" which doesn't allow the ECU to control the A/C anymore, I'd rather mod something else to make my car like one of the cars where the A/C works like stock even after the PFC is installed. Does this make sense??

 

It is a PFC design error which Apexi does give a **** about fixing, but some have had better luck with the newest version of the PFC.

Acts like a floating ground. Cars with factory AC seem less prone to this problem. My March 92 made R1 had the problem untill I install a new engine harness. This solved most of the problems but once in a while speed three will not cool.

It is something you will have to live with or fix. My 2 year old fix removed the AC controll out and away from the PFC so the PF would not control engine revs when the AC came off.

Either spend $800 for a new engine harness, use my fix, move to Canada, or get rid of the PFC.

 

IMO, the directions from Apex'i are wrong, and you cut the ground wire from the a/c compressor switch

i just connected it back up (violet wire on my 93) and it worked great, except for fan speed 3

 

new engine harness is $580, not $80

 

I misses the last 0 on $800.

 

I have a brand new engine harness. Didn't do ****.

Reverted to your bypass on the ECU. Thanks Chuck. Now I have to wire up an rpm sensitive switch to turn AC off during full throtle operation.

 

mine didn't work on any setting except 1, but works on all four settings now that I've added an additional ground to the fan switch. I'd recommend trying that.

 

There was another thread about this where someone cured their A/C problems with the PFC by replacing the A/C fan speed switch.