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Old 07-04-2009, 09:51 AM   #4 (permalink)
rob13572468
the devil's advocate...
 
Join Date: Feb 2005
Location: chicago
Posts: 883
Quote:
Originally Posted by jim-clayton View Post
Thanks Michael.
I started to look at the Trinary Switch. I wasn't 100 percent sure if the Trinary
is what I needed to connect to.
you are on the right track... the AC button passes ground to the ECU via the trinary switch. it looks like the ground is passed thru to the ECU if the pressure is not low or high (need to confrim that on a working elise). the ECU then activates the compressor relay by also sending a ground.

in theory it might be as simple hooking the two together through an ignition activated relay. i dont know what the ECU does with the signals though... there might be some programmed logic in the ECU that also controls when the compressor is or is not activated like based on temperature,etc.
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