AC compressor operation with Power FC - fixed without the relay mod!
 

So I have been dealing with the Power FC / AC compressor issue.

With a Power FC installed, the AC compressor would only engage if I selected fan speed 1. Anything higher than that, and the compressor would kick off. Of course, if I reinstalled the OEM ECM or my Pettit Unlimited ECM the AC would work perfect...

I had read about some having some luck getting correct AC function with a Power FC by replacing the fan switch...my fan switch had a broken mount so I thought it would be worth a try. So, today I installed a new switch (using dielectric grease on the plug contacts), and happily, it restored correct AC compressor function on all fan speeds! Presumably, the fan speed switch had built up some resistance over the years and the PFC could not handle it. But with a new switch, all is good again (at least, for now).

Just thought I would pass this on, if your FD is suffering with AC compressor issues it may be worth a try to replace the fan speed switch (about $80). It is a bit of a hassle to install but could be worth the effort.

Wow, that's awesome!

I assume you're talking about the switch on the center dash that you turn to select speeds 1-4? Do you have the part number handy?

Really good find!

Dale

Yep, that is what I replaced. The fan switch part number is FD01-61-C50, it's still supported by Mazda. Not sure if the dielectric grease is needed but I am using that on all connections on my FD as I replace/repair things so I thought it wouldn't hurt.

I am hoping that this repair lasts awhile, I really didn't want to have to cut into/mod my AC wiring just to accommodate a design weakness in the Power FC.

Now, if I could just get the pulsing boost on my primary turbo sorted out... :-/