1956 Cad A/C idle speed up

[jgreene]

I cannot find anywhere in the manual and example of the wiring to the vacuum speed up on my '56 Cad A/C.  Years ago a mechanic who didn't know any better grounded it to the valve cover to get it to work in drive (it only works when you put it in neutral.)  Now the wires are disconnected into the speed up unit at the back of the Carter carb.  One green wire comes out of the firewall wiring loom, and one green wire comes from the A/C compressor.  Which wire goes in the top and which wire goes in the bottom of the unit.  Also, should you be able to energize the clutch with just the ignition on and the a/c on?
Another question---how hot should the rheostat get in the control unit under the dash?
Sorry for all of the questions, but THank You.
Jim Greene

[J. Gomez]

Jim,

Attached is the wiring which includes the missing pieces for the manual. The idle speed up control only works when in park or neutral, that is power only get to the solenoid under these conditions.

1-The idle speed up solenoid has no polarity so any hook up will work.
2-The positive 12v is feed when the vent on/off switch is switched to the on position. The negative is picked up from the starter solenoid “Hold” coil which one side is grounded.

Now there are the fan speed control and the temperature control rheostats, which one you are referring to?
The temp control should not get hot however the fan speed one do slightly warm and possible hot if the fan motors are defective.

Hope this helps..!

[jgreene]

Thank you for your quick response!  The rheostats I am referring to are for the fans in the trunk.  They seemed to get pretty warm.  They work fine following the switch along--I thought it might be the rheostat causing the heating issue.
Also, do you know if you can energize the clutch on the compressor by just turning on the ignition, and switching it to on?  I wanted to check the clearance.
Thx
J. Greene

[J. Gomez]

Jim,

Yes you can energized the compressor solenoid, you will need to set the temperature control to full by-pass to extend the +12v up to it.

If you are just checking the clutch gap clearance I would suggest of disconnecting the wire directly at the compressor and applying a direct +12v there instead, this way you have control.

Good luck..!