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Discussion Starter #1
Everything I read leads me to believe my 72 XR7 convertible 351C 2V FMX with A/C has an idle solenoid to increase curbs idle when A/C is on.

Mine is on always 12+ V when the key is on and nothing I do with A/C controls has any effect at all. It acts like an anti-run-on solenoid.

I have looked at the factory wiring diagram and got totally lost when it seemed to go to an ambient air sensor of some kind!
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Anyone know how and why this thing is supposed to work? The idle spec seems to say curb idle should be 500 A/C off and 800 A/C on with choke fast idle of 1200. Be nice of it actually worked that way.

Suspect one of you is much better at reading Ford wiring diagrams than I am. Picture is the connector at the top of the left valve cover that seems like the obvious place to wire it. Think I may just give up on that and splice into wire going to A/C compressor.

Am I way off base here?
 

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Okay ... I'm sure someone will jump in and correct me if I am reading it wrong ...
on wiring diagram page 2 of 4 17/18 and H is your throttle positioner solenoid that is wired to C21 Amb. sns. switch ..note says on cowl above glove box closed at temp above 60 degrees .. that to means it is a fast idle for temperature only.

on wiring diagram page 3 of 4 32/33 C to J is your air conditioning wiring it is NOT wired to the throttle positioner solenoid any where that i can see...
 

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Discussion Starter #5
Thanks. You are seeing what I did. Makes no sense to me however. Why would they arbitrarily want to bump up curb idle a few hundred rpm just because ambient was above 60F? It makes complete sense to do that if A/C is on, but I also saw no connection of A/C to solenoid circuit either. Going to just leave off for now. Rather keep the top down and A/C off anyhow. Might play around with just wiring to A/C clutch. I assume the solenoid doesn't draw a lot of amps. Thanks for looking. If we ever actually have real car shows again I will check out others I see.
 

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I agree it does not make sense on less it is sensing coolant temperature from the heater box ?

I also agree the solenoid does not draw much for amps and if you feel you need the RPM assist i wouldn't hesitate to wire it into the A/c or even on it's own switched circuit from inside the car.

I will keep my eyes open for other information too.

Enjoy your top down cruise ...
 
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