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After I did my head gasket on the 86 in the fall, I noticed the A/C wasn't working. This spring I realized the fans weren't coming on when hot, and I assumed I had put thread tape on a sensor that I shouldn't have. But that wasn't the problem. Upon further review, the WOT switch on the base of the carburetor that I had disconnected was the problem. :eek: The plastic connector disintegrated and I pulled it all off to prevent a short and fire.

I don't know if FI Escorts had these, but carbed ones with A/C did. The purpose was to cut power to the A/C clutch under full throttle, so you don't lose a race with a semi on the interstate and end up Pintoed. What's odd about the way Ford did these is the way the switch is hot all the time with the button unpressed, at WOT with the button engaged the switch opens. And the current from the WOT switch has to flow to the A/C computer in order for it to do anything. In other words bass-ackwards from the way you'd expect it to be wired, typical Ford. :lol:

So the moral of the story is if you have a mystery cooling fan or A/C problem on an older model with air, and you've checked all the obvious stuff remember that the WOT switch has to be working and have continuity in order for the A/C controller to operate. Spock out, Cap'n.
 

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Actually, that's a very acceptable way to wire the circuit. It doesn't matter where in the circuit the WOT switch is placed, provided it cuts power under full throttle. That can be before or after the cabin push-button switch. At least they didn't have some funky full steering lock cutout switch.
 
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