Pinto Car Club of America

I am in the middle of a turbo swap into my 77 Cruisin Wagon using a LA2 ecu. I am also installing a vintage air system. Does anyone know what type of signal I need to send to the ecu to adjust the idling when the compressor turns on? (voltage? ohms? which pin? etc...) Any help is greatly appreciated.

As best I can recall an LA-2 and and LA-3 are direct swap ECU's. My Pin Out for an LA-3 shows:

10 = A/C clutch - A/C input

54 = WAC  WOT (wide open throttle) A/C cutoff

There were also two fan control signals one of which might be relevant to the A/C:

52 = HEDF Highspeed Electro-Drive Fan

55 = EDF    Electro-Drive Fan (low speed)

Hope this helps. At the moment I don't have the "type" of signal sent only where they are going/coming from. Are you using the factory relay box?

Wittsend, thanks. I am using a Vintage air system and its controls. I see the a/c input on pin 10 of my diagram but just not sure what kind of signal to send to it. I can easily send 12v to it when the clutch is engaged but i need confirmation that that is what it needs. I don't want to fry anything

The 87TC EVTM shows the LA2 pin #10 connected to the +12V side of the A/C clutch coil.  Note there is one of those surge protection diodes in the wiring harness connected across the A/C clutch coil to moderate the voltage spikes.  I believe this #10 pin is the circuit that opens the IAC a little to maintain idle speed when the A/C is on.

Thanks for all of the great info guys! This build would be a real struggle without this site and all of your knowledge and help.