S54 and AC

[E30Strube]

I'm finally trying to hook up my AC and need some help with the wiring. Since the thermostat is gone, the wiring seems a bit different. Should I simply connect the blk/red wire from the body harness to the pressure switch in the dryer and then run the black wire from the pressure switch to the compressor? There doesn't appear to be any further connections on the body side to connect to the compressor to engage the clutch.

Also, does anyone know the connector part number for the wire that goes into the pressure switch?

[nando]

don't you want to hook this up to the DME? it does important things like increase your idle speed so it doesn't stall.

[E30Strube]

From what I understand, the idle bump on the S54 is minimal, plus it is handled via canBUS which is no longer on the car anyways. Basically no way to give a "bump". Still need to connect to the compressor though.

[evandael]

yes, the idle bump is integrated with the canBUS on the e46.

since the e30 a/c circuitry is body-side and effectively divorced from the engine harness, just hook up the compressor. i think the connector number is c211.. this is a picture of the stock e30 idle bump circuit.




if the car stalls perhaps you can have it reflashed to raise idle speed.

[E30Strube]

As a positive, the idle speed can be bumped to a few different levels using a bmw computer or even modulating it at the throttle control at the end of the throttle bodies.

How does the pressure switch at the drier get connected then?

[nando]

Raising the idle speed is pretty easy. Stock target is i think 850, 950 would work and not be too obnoxious.

Sounds like a hardware a/c input would be a valuable feature to work on though. :)

[E30Strube]

Just to follow up on this I believe I have it worked out. There is another connector with two wires (black/white and red/black) that plugs into the pressure switch. The single line that used to go to the thermostat goes directly to the compressor. I also want to say my idle is already bumped up to 950.

[evandael]

wonderful. now take pics of your car!

[Staszek]

Did you get this to work? I know its an old thread.