'66 DeVille Climate Control - Help!

[Gary H. #18197]

I recently lost a water pump coming home from a show.  Shortly after that got fixed I noticed that the Automatic Climate Control stopped working.  Don't know if the two incidents have anything to do with one another, or if it was a coincidence.

At any rate, the system acts "dead".  Are there any rather quick, simple checks I can make myself before handing it over to someone who knows how to write up a big, fat invoice?  The wire feeding the blower motor has juice, so I'm at a loss as to whether it's something in the Climate Control electronics itself or the blower motor?

[greg surfas #1`5634]

I recently lost a water pump coming home from a show.  Shortly after that got fixed I noticed that the Automatic Climate Control stopped working.  Don't know if the two incidents have anything to do with one another, or if it was a coincidence.

At any rate, the system acts "dead".  Are there any rather quick, simple checks I can make myself before handing it over to someone who knows how to write up a big, fat invoice?  The wire feeding the blower motor has juice, so I'm at a loss as to whether it's something in the Climate Control electronics itself or the blower motor?

Gary,
What does "dead" mean? When you move the mode selector to "defrost" does the fan come on? I would first check the vacuum lines in the engine compartment, with particular attention to those three that attach to the heating water valve on the right fenderwell. Should those be connected and (better check carefully) free of leaks, try, with the engine running and the selector in "High" to press up from the bottom of the master swithc, the one on the right side of the firewall where four small vacuum lines come together in the top,.  If the fan and the compressor start when you press up and you hear/feel the switch click, the problem lies sin that circuit.  After years of chasing gremlins in automotive AC systems I have learned that small simple steps are the easiest way of finding problems.  Check out the above and let us know.
Easy does It
Greg Surfas

[35-709]

A 1966 Cadillac Shop Manual might well do a world of good in this case.  Relatively easy to find on eBay or from the several re-printers that are out there such as Crank 'en Hope and others.

[cadillactim]

If the system worked fine before, then you should be able to get the fan to come on in the Defrost setting.  If the fan is inop in any position check the fan by using a jumper wire straight to the fan terminal.

I have a simple troubleshooting and diagnostic file you can download and print, shows how to test and isolate each component of the system.  Just log ont my website www.cadillactim.com and click on the "Tech Help" tab.  There you will see the 1964-68 Climate Control Troubleshooting.  You can also call me if you still have more questions (phone number on website).  Tim