Automatic Climate control '67 De Ville

[Julien Abrahams]

Hey guys, I have an idea to tackle the climate control system problems in my '67. The airconditioner compressor is off the car,and the condesner removed, so its not going to get cool. Thats fine with me. However, it seems as though the system is on max. heat all the time, regardless of the setting on the dial. The blower works (low speed in vent, & lo settings, hi speed in ice setting). Do any of you guys have experience with this system? It will be a "summer project" anyway, so any advice on this is appreciated. I've got the manual as well, and i've got some ideas.
I just would like to be able to set it to heat (handy in the winter) but I also want to be able to turn it off, as my feet get roasted in summer .

["Cadillac Kid" Greg Surfas 15364]

First thing to check is whether all the control side components are installed and connected.  Check the fuse at the fuse box and check to see the transducer (under the dash on the passenger side) is connected AND grounded.
Greg Surfas

[Scot Minesinger]

The shop manual is very helpful.  Another great resource is the Climate control manual (one for each year) by Tim Groves, google Cadillac Tim in Iva, SC.  He takes all the info out of the manual and add some of his own experience/  It is much easier to use than the shop manual.

I restored the 1967 Cadillac Climate control that won first place in GN 2013 (P22), in March of 2013, so that is still fresh in my head if you have any questions:  rscotm@cox.net.  On that car the only thing I did not replace is the condenser, the fiberglass casings, some wiring and the blower motor.  All else was replaced - all controls, all vacuum hoses, servo, dash unit, transducer, compressor evap, heater coil, blower wheel, evap, misc, and even the air directional blades inside the evap fiberglass casing.

Good luck,

Scot

[Julien Abrahams]

Hey guys, caution: very long post .
Just a quick update and a couple of questions on the Climate control. So, it turned out that some previous owner had bypassed the transducer, causing the system to be on full heat all the time. By the looks of it, for quite some time, as the Power servo valve was a bit stuck. As the car is not running, I decided to just check all individual components and later use an external vacuum supply (from example from another car) to see what it does. In my view, if you have a vacuum supply where it normally connects to the intake manifold, the system should work when the ignition is turned on.
So. It turned out that by the looks of it, all vacuum diaphragms hold vacuum, and the voltage to the transducer works and is correct and changes when changing turning the temperature dial. When I put an external vacuum source on it, the system worked fine in Vent mode and Ice (like before). The only thing I wasn't able to test is whether it actually blows heated air (as ofcourse there is no hot coolant circulating the heater core). However, in Auto, Lo and Hi positions, the blower does not come on. It appears that there is a vacuum leak somewhere, as the blower stays on for a couple of seconds when moved from Ice to Hi position. But where?
I took the Power Servo valve apart and sanded it with 500 and 1000 grit sandpaper to flatten it (it was a bit warped). All vacuum hoses are good. So the things that hold vacuum:
- Hot water valve
- Heater shut off valve (time delay is not present, connected directly to heater water shut off and thermal vacuum valve).
- Neutral safety switch and emergency brake release actuator
- Outside air/recirculating diaphragm
- A/C - Heater mode door diaphragm
- Defroster door diaphragm
- Transducer
- Master on/off switch.
Also there is no fast idle diaphragm (line is properly plugged).

I checked all of the above by connecting hose to the individual holes in the connector for the control head valve and power servo valve.
I added two pictures, the vacuum diagram (from the manual), and the internal connections the Power servo vacuum valve and the Control head vacuum valve make in the Max A/C and Auto positions respectively. The pic from the internal connections are taken from the manual (Paint was my friend .

A couple of questions:
- Is it normal that all of the connections on the Master switch are connected to each other? In the sense, when you put vacuum on one of the hoses, all of them get vacuum through the Master switch?
- The vacuum schemes have got me a little confused. I couldn't quickly find a nice picture of the internal connections of the power servo and control head vacuum valve, so bare with me on this one. I connect the hose that normally connects to the engine manifold to an external vacuum supply and plug the hose that normally connects to the power servo vacuum. So the Power Servo valve, will be in the position equal to when no vacuum is supplied to the vacuum diaphragm of the Power servo (being max A/C mode).
When the selector is in the Auto position, the internal connections of the control head valve result in terminals 1, 6 & 7 to be supplied with vacuum.
--> 1 is main feed from vacuum source.
--> nr. 6 on the control head is connected to the defroster door diaphragm (so air out of air ducts, not to windshield) and nr. 6 on the power servo valve.
In the power servo, 5 & 6 are connected (see vac internal pic) so, I believe that nr. 5 on the power servo also has vacuum, pulling the A/C heater mode door diaphragm close.
--> nr. 7 (on control head) connects to heater water shut off valve, shutting off the hot water. It is also connected to nr. 4 on the power servo valve.

In the Power Servo valve, Nrs  2, 3 & 4 are connected (where nr. 4 is fed from control head valve).
--> Nr. 2 should pull the Master On/Off switch close.
--> Nr. 3 also has vacuum, and does something with the Hot water valve (I don't exactly understand what, but I presume it closes it). It also connects to nr. 4 on the control head valve, which in turn is connected to nr. 5 on the control head valve for the fast idle diaphragm (which in my case is plugged).

So how come the blower motor shuts off when I put it in Auto, Low or Hi?  (indicating a vacuum leak somewhere, as suggested by this link: http://www.modifiedcadillac.org/articles/Climate1.html)
How can there be a vacuum leak present when all of the individual components holds its vacuum (I tested this by hand/mouth > suck on the tube that connects to for example a door, and put your tongue on it to see if it holds vacuum) ??
It just appears as if there is  a leak through the master switch. When I pull one of the hoses on the Master switch (doesn't really matter which one), and plug the connection on the Master switch with my thumb, the blower comes on.
My next step is to manually make the connections that he power servo and the control head valve should make (with some tubing and stuff). Any other ideas?

[cadillactim]

By disconnecting one of the vacuum lines on the master switch and plugging off the port to make the blower come on shows you have a vacuum leak somewhere. Putting the dash control in ICE to get the fan come on is another sign of a vacuum leak.  When in ICE, there is not as much vacuum leak, which allows the master switch to work.  It takes about 8 inches of vacuum to "overcome" the spring pressure in the master switch, but only about 4 inches to keep the switch closed. This is why the blower will stay on for a little while when you put the lever back to Auto. But when the vacuum drops (under an engine load), the switch will shut back off.

If you did not properly lubricate the rotary valve it will scratch and leak vacuum again.

The manual I have is detailed on troubleshooting this system.

Tim Groves (Cadillac Tim)

[Julien Abrahams]

Is it possible that the control head vacuum valve is warped? I do feel a bit more resistance when moving the lever from auto to hi, fog or ice, or is this normal? I will take the power servo valve out again, sand it, and properly lubricate it (thin film of wheel bearing grease?). Or does anyone know the Dutch equivalent to the dielectric grease that you get in the states?

[cadillactim]

Vacuum grease is the best thing to use.  Vaseline isn't lasting since it will melt.

The rotary valve on the dash control can be leaking. Sometimes you can spray some penetrating oil in the holes and move the lever back and forth several times, and often that will clean out the debris in it and make it seal better.

Tim

[chrisntam]

Where do you buy or who sells "vacuum" grease?

[Scot Minesinger]

 I bought it at Advanced Auto, and I'm sure other's have it too.  It is a thick grease that given a close clearance it will seal and lubricate.  I think it is called pressure grease or something like that.  When you buy it even the smallest container (under $5) is a lifetime supply for someone who works on climate control 24/7.

[cadillactim]

Here is a link on ebay.

http://www.ebay.com/itm/DOW-CORNING-Laboratory-High-Vacuum-Grease-976V-Stopcock-/280617417858?pt=LH_DefaultDomain_0&hash=item415619fc82

Tim

[Julien Abrahams]

Just a quick update. I believe I have found the problem. I didn't put the power servo valve together the right way . stupid me. Cleaned it, greased it, put it back together, and it appears to work as it should. Cool:).

[Jeff Rosansky CLC #28373]

What is the best way to check a transducer?
I have one for a 70 and one for a 67 I think.  If I put power to both of them, there is no change in the vacuum.
Jeff

[Julien Abrahams]

Is it in a car, or just separate. The transducer responds to a change in voltage coming from the amplifier (which in turn amplifies the voltage (12V from the ignition) multiplied by the resistance coming from the sensors and the temp. dial, so that the transducer gets a voltage between roughly 3 and 8 volts). In response, the transducer changes how much vacuum is "let through". It is connected to the vacuum storage tank, and the other end is connected to the power servo valve. The easiest way is to hook the transducer up the way it should. Start the car. Put the temp. dial on 65. Probe the wire that goes to the transducer with a voltmeter. Rotate the temp. dial, and watch the voltmeter. When you slowly turn the dial to 85 degrees, the voltage to the transducer should drop from about 8 volts, to about 3 volts. At the same time, the power servo should arm should move. You can watch the arm which should move towards the drivers side when the temp dial is moved from 65 to 85 degrees. Then you know your transducer is ok. If nothing happens, then your transducer has passed away .

[richardbergquist]

How difficult is it to take the Head Control unit out? I’m having good vacuum going into the unit but no vacuum coming out of it. Anyone has a picture of the head unit out and disassembled?

[DeVille68]

I can show you some pictures of my 68 unit. Not sure if it is identical, but I suspect that the rotary vacuum valve is warped.
You should find a pretty good description in the shop manual of how to remove the unit.
Otherwise I can scan this for you. (I have the 68 version)

Best regards,
Nicolas

[savemy67]

Hello Richard,

You may want to read Gerald Loidl's website (http://www.eldorado-seville.com/files/tag-1967-cadillac-repair-tip.php) where he does a little trouble shooting of his '67 DeVille's control head.  He also repairs the rotary valve in the power servo.

Christopher Winter

[richardbergquist]

Thank you for the pics! I took it out and it seems that the spring that holds the rotary valve fully closed was broken. I’ll see if it gets any better after reinstalling it.

[richardbergquist]

Second pic, when switch closes as the pin hits the metal wheel sparks fly and everything gets very hot, plastic has melted.