News:

Due to a technical issue, some recently uploaded pictures have been lost. We are investigating why this happened but the issue has been resolved so that future uploads should be safe.  You can also Modify your post (MORE...) and re-upload the pictures in your post.

Main Menu

Air Conditioning in my 1964 Sedan De Ville

Started by Bob Sweeney, May 02, 2019, 10:58:35 AM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

Bob Sweeney

Hi guys,

I bought this beauty a year ago and at that time the AC system was flat.  I replaced a line that had a huge hole in it, pulled a vacuum, charged it with R12 and it started making cold air !!!! Oh happy days !!!

AC runs great until I take the transmission out of Park (and put it into Drive or Reverse).  At that point it just fan shuts down.  If I put it back in Park the fan starts blowing cold air again. 

What the heck ?   My only thought is that it might have something to do with the neutral safety switch (it hisses when I put car in Drive). 

Any suggestions ??

Cadillac Fleetwood

Page 13-20 or 13-22 of the 1964 shop manual (I don't remember which) has a vacuum circuit diagram which shows that the vacuum input to the neutral switch is interconnected with the vacuum input to the dash control head for the climate control. I would suggest a review of that diagram, and checking all fittings for leaks.  The hissing of the NSS could also indicate an improper adjustment.  Does the car start only in P and N, and not in any other range?  Do the reverse lights turn on in reverse, and not in any other range? The shop manual provides some instructions on how to adjust it.

-Charles
Forty-Five Years of Continuous Cadillac Ownership
1970 Fleetwood Brougham
1969 DeVille Convertible
1989 Fleetwood

"The splendor of the most special occasion is rivaled only by the pleasure of journeying there in a Cadillac"

Dan LeBlanc

If it hisses that bad and the hoses are not disconnected, the switch is bad. It's creating enough of a vacuum leak to disable the climate control (I believe the steamboat switch needs vacuum to turn on the fan). All that controls at the switch is the automatic parking brake release anyway. Disconnect the supply line at the switch, plug it (golf tees are great for this) and see if that works. If so, leave it plugged until you get another switch (if you want to use the automatic parking brake release).
Dan LeBlanc
1977 Lincoln Continental Town Car