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idle switch possible for air conditioning?

928 Views 5 Replies 3 Participants Last post by  Tifosi
My 86 Spider has a lightened flywheel and does not handle the AC compressor well, sometimes it even kills the motor. I have a great, smooth warm idle, so I would rather not increase my idle speed.
There are two Bosch relays under the hood that seem to be associated with the AC- wires have been cut from these by a PO, so I'm not sure of the proper wiring (or if they should even be there from the original dealer install). One relay is working properly for the electric fan at the front of the condenser, and I wonder if the other was supposed to tap into the coil and computer to alter idle speed when the compressor is engaged. Does anyone have a properly wired setup like this, or better yet, a wiring diagram?
If this was not the original intent of the second relay, does anyone have any suggestions for an idle speed switch for Spiders of this era?

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Both relays you describe are relative to the secondary fan.

One allows the fan to come on when the AC is turned on, the other works in conjunction with the temperature probe that (should be) mounted to the left side of your radiator shroud which detects when the temps comoing off the radiator are too hot and engages the auxillary fan. (which will run after you shut down the engine and automatically turn the fan off once the senosr gets cool enough)

I'm 'pretty' sure there's a diagram in this section or the elecronics subsection.

However, if not, papajam may have something covering that circut that he may offer up if you PM him about it.
Thanks! I was searching for the wrong thing before- photos and the wiring diagram are here for those interested:

Is that temperature sensor available anywhere? Mine is long gone...

Also, I don't suppose anyone has any ideas for my original AC idle problem? I could fabricate a mechanical stop on a relay that would hold the throttle stop slightly more open when the compressor is on, but that will be quite an effort, and it seems that there should be a relatively easy way to do this electronically.

Some Milanos use an idle air device for the A/C. It's electrically operated & plumbed into the intake. When the A/C compressor cycles on, this device receives voltage & opens. It has one line that goes to a fitting of the flow meter hose & another line that attaches to the intake behind the throttle body. When opened, it allows additional air into the motor at idle. It might be possible to plumb this into your Spider's idle circuit with some T-fittings.
That seems like a good way to accomplish what I am trying to do. What years did the Milano use these, or better yet, does someone have a part number and/or photo?

Still also looking for any ideas on where to find the AC underhood temp sensor- IAP doesn't apprear to have them.

Alfa Parts Exchange mabe?

It'll be off a stripper car, but it is one of your better chances at finding one.

Or, you 'might' be able to pick up a stick-on thermostatic switch for an aftermarket electric fan at a local parts store if originality isn't the issue. (and they'll sell you a switch without as fan)
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