Last weekend, I was trying (vainly) to remove the blower motor cover in the engine compartment when I noticed something strange:  A black rubber hose, originating from a vacuum actuator on the passenger side of my Carter carb, that went nowhere.  The previous owner had carefully tucked the free end underneath another vacuum actuator attached to the blower motor cover.  There was a plastic nipple stuck in the free end of the hose, meaning the other end led to another hose.  I looked everywhere and the only piece of hose within reach of the tube was hanging out of the firewall, along with a bunch of wires.  I plugged it in and tested the car but noticed no difference.  

Did I plug the hose into the right place?  So much is missing/not plugged in on this car, particularly windshield wiper assembly, washers, etc.  So I don't know.  One thing is sure, the black hose coming out of the vacuum actuator on passenger side should plug into something, somewhere.  

As usual, the manual is no help whatsoever; no photos, no description of what I'm talking about at all.  But here is a photo I found on the Internet showing my setup.  Any ideas???  Thanks!

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Comment by Lee Martin on May 18, 2016 at 12:47pm

I see, thanks Jason, Tony & Ginny.  That explains it, now I know why I didn't notice a difference after plugging it in—my AC doesn't work either. :)

Comment by Jason Edge on May 17, 2016 at 8:13pm

Tony, 1963 Cadillacs with AC, regardless if they were equipped with the Carter AFB or Rochester 4GC, had the idle speed-up control.  Of course, over 50+ years they were often removed as carbs and other components were replaced. With out it, it just means your car is idling lower (480 if set to factory specs) and a bit more prone to overheating when idling in Park or Neutral on a hot day  with AC on (or knocking off) if not properly tuned. :-)

Comment by Tony and Ginny 429 on May 17, 2016 at 7:25pm
From Jasons post above ,looks like --some --63- 390s came with the Carter carb , and the idle up ,for the A/C , so go with Jasons info on the 63 carbs
Comment by Jason Edge on May 17, 2016 at 5:05pm

Lee, The vacuum actuator on the RH rear of your car is for the  Air Conditioner Idle Speed-Up Control. It is described in your 1963 Cadillac Shop Manual on page 13-21:
An idle speed-up control is used to boost engine rpm when transmission is in "Neutral" or "Park" and the Air Conditioner is "On". This improves engine cooling and Air Conditioner performance when the car is standing.
It is illustrated on the Rochester Carb on page 10-12 and on the Carter AFB carb on page 10-23. Idle speed-up control adjustment is on page 10-33.  The vacuum schematics are on page 13-18 where it shows it is the blue striped vacuum line that goes from the AC-Heat Control Panel to the Fast Idle Vacuum Unit (AC Speed-Up Control).

Comment by Tony and Ginny 429 on May 17, 2016 at 3:44pm
The Carter carb was put on the 429 , in 1964 ,( to the best of my knowledge ) and the vacuum valve in the picture on the side of the carb ,is for the 64 comfort control ,to raise the A/CS RPM at an idle
The 63 does not have the - comfort control - heat and A/C system , that the 64 does ,as it was a new design for 64
Looks to me like that carb was installed on you 63 - 390 as an upgrade ,as it is a better carb design advancement ,in my opinion
The best new carb design ,when it was released , in this time period
Comment by Tony and Ginny 429 on May 17, 2016 at 3:28pm
Not sure what the picture of your carb ,has to do with the hoses you are referring to ?
Post a picture of the hoses in question , so we can get a look at what you see


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