Can anyone tell me where the 2 wires coming from the air conditioning pressure switch (under the battery tray) go to? The only wiring diagrahm I can find online is the "Mitchell's" one at www.iluvmyrx.com but it's for a 93 FD and my 94 FD is a little different. On the 93 FD one wire comes frome the AC Relay to the pressure switch then the other wire goes from the pressure swith to the magnetic clutch. On my 94 FD the wire comes from the AC relay straight to the magnetic clutch and the two wires from the pressure switch go into the front engine harness and are routed along the right (passenger) side entering (I assume) somewhere into the right side kick panel area. The AC was working okay, I'm just verifying the harness wiring after some repair work I did to it.

 

So, does the AC work? If so, the switch is doing its job.

I haven't studied the AC diagram too much, but typically the pressure switch is in-line with the signal to switch the compressor on. Too low or high pressure, the switch opens, the compressor doesn't get 12v, no AC.

If you're testing wiring, you can jumper the connector to bypass the switch and test for continuity if you're worried about bad wiring somewhere.

BTW, I'd HIGHLY recommend buying a real shop manual. Last I saw, Mazdaformance had them on sale for like $40-50 or so for the small ones. You'll reap a lot of reward from that money spent.

Dale

 

Thanks for the response. The AC is working okay, I'm just verifying the wiring while I'm in the harness. I agree with you about the pressure swith typically being in-line with the compressor and when I saw the way this is wired it got me wondering just how it works.

 

Does anyone know the trigger pressure values for too low and too high ?

For R134a, I've typically seen 2-bar low, and 30-bar high (1-bar = 14.5-psi)

:-) neil