jimshih

Ok I had no A/C since I installed PFC. My compressor won't engage in any fan position.

I did some search and a weak fan switch sounds reasonable. I ordered a new one from Ray but just didn't get around to install it.

Finally decided to give it a try yesterday. I took apart my practice FD first. After I learned what not to do I started on my CYM.

I found I could get the center panel to come out by just moving the cluster to the side. No need to disconnect the wires in the back and take it out which would possibly put some more scratches in the plastics.

Put the new switch on and still nothing. What the???

I put my old ECU back and the AC works perfectly.

Did some more searches and found one posting about the thermo switch behind the glove box.

This is a temperature-controlled switch, which will cause bad grounding as well.

I used a c clip to jump the two wires together bypassing the switch.

Bingo the AC works in any fan position now.

I was going to switch the switch between the two cars but they look different??

There is a temperature probe going into the plastic box and I couldn't pull it out maybe the box has to come apart to change it.

So I will run it as it for now just need to turn the A/C off once in a while to keep it from freezing up.

Just in time as it is getting warmer and warmer.

DaleClark

iTrader: (55)

Interesting. Weird thing is the AC in my '94 R2 works PERFECTLY with the PowerFC - never had a hiccup.

There are 2 different AC systems - the Tourings had a Nippondenso system that was installed in Japan, and the base/R models had one that MANA (Mazda US) installed at the port. Supposedly one is supposed to be more compatible than the other.

The temperature probe you're looking at cuts the AC off when the evaporator (the AC core under the dash) gets to a certain temp. If that didn't happen, you'd get ice in the evaporator, which would block airflow and be bad in general. Unfortunately, I think it's some pretty un-fun work to swap that temp probe out, as it's pretty built into the evaporator.

You might be able to get that temp switch for the evaporator and figure out a way to install it into the evaporator without taking the whole thing apart. Might be tricky, but since you have a "test car" that may help you out. But, this is a VERY good thing you found - the AC problem is a real tricky one!

Dale

Thomas1277

Not to take over your post but I have a problem with the ac cutting off when the fan is on 3 or 4. The ac works fine on 1 and 2.

DaleClark

iTrader: (55)

That's typically a problem with the fan switch itself. Search the PFC forum for more info - it's been covered quite a bit.

Dale