Well it finally died....stock ECM in my 98

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TTSaleen

TTSaleen

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This is the diagram I pulled. It looks like the pcm controls the pink/yellow wire on pin 22 at the ccrm. We could control that same wire, but it would also require you to give the terminator an input signal to let it know you want the ac. This would use up one of your inputs and one output. View attachment 22509

Thanks.
Yes (correct) the AC just won't engage the compressor when I turn on the switch on the dash.
I have voltage on the purple feed wire out of the in-dash switch panel when I turn it to AC (12 volts).
I have voltage across the AC pressure switch located on the dryer.
I have voltage across the AC pressure switch (high side) located on the condenser.
It appears I don't have voltage out of the CCRM to the black/yellow wire that goes to the actual compressor connection.

So I'm over the whole CCRM at this point.
I took a 30 amp relay and used the Dark Green/Orange as my trigger wire and used the Black/Orange as my main power feed (12v) and now I can get 12v to the Black/Yellow wire and the compressor comes on and the car cools fine.
I also added a 2nd relay that when triggered by the AC on, will ground the signal to the 2nd cooling fan.


Only thing left is if I want to incorporate the AC shutdown feature using the Holley at WOT.
But for now, the AC works!
Thanks for all the help!



1998_Mustang_AC_wiring.png
 
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NXcoupe

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We used the pcm signal wire out of the PCM and grounded it through the holley. I can't recall exactly the parameters but it was under like 75% throttle and over 300 rpm, as long as these 2 parameters are met, the ac will kick on qith the switch on, but will not engage the clutch when the key is just turned on. We also used this input as an ac kick for idle and used it to light off the high speed cooling fan. Holley's have endless potential.
 
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TTSaleen

TTSaleen

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Couple pics from last weekend.
Drove it to work and it is running fantastic. I should have converted to a Holley years ago!
Plus running on E85 is great (other than gas mileage is noticeable less) LOL.

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