68 DeVille heater

[rustytractor]

One of the contacts on the firewall mounted fan control vacuum switch on my 68 has broken so the fan wouldn't turn on automatically - easily fixed temporarily with a flick switch mounted inside but there's a problem getting both heat in and controlling the vents into the car.

I've spliced power from the flick switch into wire that supplies voltage to the fan and whatevever controls the fan speed is obviously working because in the auto position the fan speed auto adjusts whereas in the "HI" or "LO" position the fan runs fast or slow. To me this indicates that somewhere in the system the temperature is being correctly sensed but the (vacuum ?) vent controller isn't working. There are issues with hardened vacuum pipes on the car in general which I suspect are at least part of the problem.


Is this in part controlled by the same firewall mounted fan control switch I mentioned earlier or something else ? This is my first experience with a 1960's Cadillac so I'm learning as I go which is fun.
Other than this problem the car's running great since we rebuilt the heads last week and fixed a number of little jobs like fixing the central locking etc. What a smooth driving car !

[Scot Minesinger]

One of the best thing about this forum is that someone has been through this before, probably multiple people on a 68 Cadillac, which to me is one of the best years ever.

Anyway to your question:

1.  The bet way is to put the car back to normal, if these flick switches would resolve climate control issues, believe me that is all that anyone would use.  Buy Cadillac Tim's (Google "Cadillac Tim, Iva, SC) book on 68 Climate controls - it is a must - plus he sells all the parts too. 

The car was set up sot that a sensor in hot water heater valve allowed vacuum to enable system once the valve was warm so that cold air would not blow on occupants until car was warmed up.  There were three vacuum hoses connected to original heater valve, the top one connected to valve actuator opens and shuts valve.  The other two are connected when car is warmed up.  You could (and many do) by pass the thermal switch on valve and connect them together, then the heat would not be delayed, which is Ok to me.

2.  That "steam boat" switch you refer to was used from1965 thru 1968 (so like 3/4 million were made) and used, re-built and I think even reproductions are available.  Replace it as step one and get rid of the flick switch.

3.  Usually when the climate control system originally fails, the system becomes inoperable, and as the period of inoperability continues for decades more things fail.  On a 68 Caddy, you are probably looking at replacing power servo, dash unit (amp goes), transducer, and steam boat switch plus of course all vacuum lines under the hood.  The under dash hoses can be disconnected and the ends snipped off, then re-attached.  The plug into dash unit and servo, which is a hunk of rubber are good for a while (never had to replace one).  Of course these four items should be tested, not just replaced, because most often the replacements are rebuilt with used parts and may not be as great as an NOS.  The vacuum lines under hood should all be replaced.  USA Parts sells the color coded vacuum lines.

4.  As the climate control system fails over time, people add flick switches and all kinds of stuff to jerry rig it, those need to go.

5.  You could make this an all flick witch thing, but many switches and complications would result, because the air needs to be switched from floor, to dash to windshield.  Then you need to make sure fan is on when compressor is on or you ruin compressor.  Need to make sure compressor never turns on when below 32'F.  Need multi speed switch for fan - it just turns out that the original climate control is easiest, plus retains value ( a make shift flick switch set up lowers value over original-both operating comparison -this keeps your options open).

This is a good winter project.  Buy Tim's book and get started-it is a nicer more comfortable system than any new car when it is fully functioning.

Enjoy your 472 Cadillac!

[rustytractor]

Thanks for the detailed explanation - as I mentioned in my post the flick switch was a temporary solution only and at least it made the fan run and got some warmth into the car on a cold day. I had a promo job in Central London for Benefit Cosmetics and had to arrange six Cadillacs of which the '68 was one so the flick switch was a necessary evil. 

The cars were:

1956 Fleetwood
1957 Sedan
1959 Sedan
1962 Eldorado Biaritz Convertible
1964 Coupe De Ville
1968 Deville

The '68 is a really good car with very few needs - other than the heater issue and non-functioning clock she's good to go.

["Cadillac Kid" Greg Surfas 15364]

Russel,
First of all, where was that picture taken? It looks very familiar and I've only been to London once.
Back to the subject.  IF when you cross the two wires connecting to the master switch and you get heat and ac you are ahead of the game.  You stated that you get modulating speed fan.  Is that when you rotate the temperature selector dial from 65 to 85 degrees (F for you in C land)?
If so again you are correct in your diagnosis and it seems your temperature controls are functional.  The lack of control over the air distribution direction could be the symptom of vacuum leaks on that side of the controls.  What I would do IF THIS WERE MINE is to replace the master switch first paying careful attention to the vacuum lines in that area.  Check for split ends, leaking hoses or even just disconnected hoses.  What I would also do at that point is to take the two vacuum lines that plug into the side of the hot water heating control valve and connect them to each other using a coupling.  With that done chances are pretty good that the system will function correctly.
Although they produced tens of millions of cars from about 1960 through 1972 that used the master switch they seem to have never been picked up by an after market manufacturer, and NOS units can be quite dear.  The last new on I bought was around $300.00 (USD).  Although you CAN get "rebuilt" or rather refurbished units, I believe the shipping to the UK is such that it warrents finding a new unit.  For that I would suggest this classifieds "Parts wanted" section.
Good luck with the project and if nothing else they teach patience.
Greg Surfas

[cadillactim]

You probably have vacuum leaks, very common on these systems. Rotary valves like to leak on these, affecting air delivery into car. Good chance when you replace the master vacuum switch you will still have problems with vacuum leaks.

I have rebuilt master switches if you need one, and overseas shipping is not bad since they aren't that heavy. And like Scot mentioned I have an easy to use troubleshooting manual, no special tools needed. Check them out on my website www.cadillactim.com


Tim

[rustytractor]

Russel,
First of all, where was that picture taken? It looks very familiar and I've only been to London once.
Back to the subject.  IF when you cross the two wires connecting to the master switch and you get heat and ac you are ahead of the game.  You stated that you get modulating speed fan.  Is that when you rotate the temperature selector dial from 65 to 85 degrees (F for you in C land)?
If so again you are correct in your diagnosis and it seems your temperature controls are functional.  The lack of control over the air distribution direction could be the symptom of vacuum leaks on that side of the controls.  What I would do IF THIS WERE MINE is to replace the master switch first paying careful attention to the vacuum lines in that area.  Check for split ends, leaking hoses or even just disconnected hoses.  What I would also do at that point is to take the two vacuum lines that plug into the side of the hot water heating control valve and connect them to each other using a coupling.  With that done chances are pretty good that the system will function correctly.
Although they produced tens of millions of cars from about 1960 through 1972 that used the master switch they seem to have never been picked up by an after market manufacturer, and NOS units can be quite dear.  The last new on I bought was around $300.00 (USD).  Although you CAN get "rebuilt" or rather refurbished units, I believe the shipping to the UK is such that it warrents finding a new unit.  For that I would suggest this classifieds "Parts wanted" section.
Good luck with the project and if nothing else they teach patience.
Greg Surfas

You probably have vacuum leaks, very common on these systems. Rotary valves like to leak on these, affecting air delivery into car. Good chance when you replace the master vacuum switch you will still have problems with vacuum leaks.

I have rebuilt master switches if you need one, and overseas shipping is not bad since they aren't that heavy. And like Scot mentioned I have an easy to use troubleshooting manual, no special tools needed. Check them out on my website www.cadillactim.com


Tim

Thanks Greg/Tim,

Having recently restored a 1971 Corvette I'm no stranger to vacuum systems - getting the headlamps and wiper door to work properly are fun to say the least ! It takes a while to get your head around the way these systems work but I'll no doubt get there with the Cadi as well. I have similar issues with my '64 Coupe De Ville so hopefully sorting one will clarify the problems with the other.

The fan speed modulates in the Auto position - please bear in mind that this was all a bit of a rush so I didn't go through any considered or documented test procedure of any kind and this was a simple matter of "oh s**t - the fan isn't running and I need it to work tomorrow so quickly whack a switch in the line so I can turn in on" kind of mentality. It did the job (well, sort of) but now a proper repair needs to be performed.

I have a few problems with the heating and a/c on the '68. The a/c is non-functional as the top take off on the a/c rad has broken so currently the compressor is disconnected and the rad removed. The rad was pressure tested ok so I just need to find someone who can repair the take off OR buy a new one.

Well spotted - I'm not surprised you recognised the location in the picture - it was taken under Marble Arch, right in the centre of London's West End. I'll try to locate a better photo which shows the arch more clearly. This is a special location to get permission to park the Cadillacs and they caused quite a stir ! 

Tim, thanks for posting - would I need manuals for both the '64 and '68 or would one give an insight into the other ?

[cadillactim]

One manual would give you the insight for the other. I would recommend the 64 manual since there were some mid-year changes to the Climate Control that year. The 68 system operates on the same principle, just not as complex as the 64.

Tim

["Cadillac Kid" Greg Surfas 15364]

Russell
I thought it looked familiar.  We stayed at the Hotel Corus /Hyde Park and we walked every foot of that area. Back to the car.  If you just jump across the two master switch terminals with your switch, the fan should operate, and with it heat.  Connect all four vacuum lines that went into the master switch together with something like a cross, and see what happens.  If there are no leaks anyplace els (vacuum) chances are goo your system is intact.  One of the thinks that is always recommended is to get a copy of the "
original" factory shoop manual for your year car.  You will find them on e-bay for about $35.00 (USD, that would be about 22 pounds on your side of the pond).  They have all the diagrams and specifications as well as an excellent technical description of your control systems, heating sytems, as well as the AC refrigeration systems that you will want when you get back to charging the AC for the 6 days a year (I think) you need cooling LOL.
By the way, I know the EU and the UK have begun a phase out of R-134a  on new cars.  How is that going to effect you in recharging your system, since I know R-12 has been illegal for quite a while.
Let us know.  I am working on a "prototype" HFO-1234yf (the replacement now currently in favor throughout) When I get the results I will post them with any modifications necessary to regain some of the stated loss of efficiency (over R-134a), If possible.
Another suggestion is that you join the Cadillac LaSalle club if you aren't currently in the process of doing so.  I know there are quite a few Cadillacs over there.  My 66 Coupe deVill was purchased by a fan in the Dorset area and next trip over I hope to make it a Cadillac trip as well as sight seeing tour.
Anyhow, good luck with your car and keep the forum up to date on your progress.  That is what it is for, one member with experience helping another.
Cheers
Greg Surfas

[rustytractor]

Russell
I thought it looked familiar.  We stayed at the Hotel Corus /Hyde Park and we walked every foot of that area. Back to the car.  If you just jump across the two master switch terminals with your switch, the fan should operate, and with it heat.  Connect all four vacuum lines that went into the master switch together with something like a cross, and see what happens.  If there are no leaks anyplace els (vacuum) chances are goo your system is intact.  One of the thinks that is always recommended is to get a copy of the "
original" factory shoop manual for your year car.  You will find them on e-bay for about $35.00 (USD, that would be about 22 pounds on your side of the pond).  They have all the diagrams and specifications as well as an excellent technical description of your control systems, heating sytems, as well as the AC refrigeration systems that you will want when you get back to charging the AC for the 6 days a year (I think) you need cooling LOL.
By the way, I know the EU and the UK have begun a phase out of R-134a  on new cars.  How is that going to effect you in recharging your system, since I know R-12 has been illegal for quite a while.
Let us know.  I am working on a "prototype" HFO-1234yf (the replacement now currently in favor throughout) When I get the results I will post them with any modifications necessary to regain some of the stated loss of efficiency (over R-134a), If possible.
Another suggestion is that you join the Cadillac LaSalle club if you aren't currently in the process of doing so.  I know there are quite a few Cadillacs over there.  My 66 Coupe deVill was purchased by a fan in the Dorset area and next trip over I hope to make it a Cadillac trip as well as sight seeing tour.
Anyhow, good luck with your car and keep the forum up to date on your progress.  That is what it is for, one member with experience helping another.
Cheers
Greg Surfas

By "Master Switch" I assume you mean the main dash mounted control switch with the auto and hi/lo selector ?

The different components of this system are all new to me so understanding which is which will help.

As far as coming to England the next time, when you're in the London area let me know so we can meet up and talk Cadillacs and I'll show you my little collection (41 Series 63, 53 Convertible, 59 Sedan, 62 Coupe low rider custom, 64 Coupe de Ville, 68 DeVille)

[cadillactim]

The master switch is the vacuum switch mounted on the firewall beside the power servo. It looks like a little tugboat, and is often called a "tugboat switch" or "steamboat switch." It has four vacuum connections on top, and a two spade wire connector.

The unit in the dash with the temperature wheel, Auto, Lo, Hi, Defrost settings is the dash control or controller.

Tim

["Cadillac Kid" Greg Surfas 15364]

Russel,
The master switch I am talking about is the vacuum switch on the engine side of the firewall that the four vacuum lines and the two wire electrical connection (that I believe you said one of the terminals was broken off, of). I have attached a "generic  (actually 1966) vacuum diagram showing the master switch and its connections for your information.

Russel with all those cars you have just moved my next trip over the pond up by at least a year.  Send me a PM clsalamo@aol.com so we can keep in touch.
Cheers
Greg Surfas

[rustytractor]

The master switch is the vacuum switch mounted on the firewall beside the power servo. It looks like a little tugboat, and is often called a "tugboat switch" or "steamboat switch." It has four vacuum connections on top, and a two spade wire connector.

The unit in the dash with the temperature wheel, Auto, Lo, Hi, Defrost settings is the dash control or controller.

Tim

Thanks for clearing that up Tim.

As I said in my original post, one of the terminals on the master switch is broken and is the one I've bypassed. I thought (incorrectly ?) that this vacuum switch, when vacuum was present from one of the four vacuum tubes, merely switched the fan on or off before it was controlled by a speed regulator.

I need a replacement for this switch, possibly two as I think the one on my '64 is also faulty. If I get one I can test it on both cars.

[cadillactim]

Russell

Sent you a PM about the master switch.

Tim

[cadillacmike68]

Russel,

Tim's books are really good.  I have a 1968 DVC (and I notice that your 1968 is also a DeVille  Convertible), and I had the, shall we say, "opportunity" to become VERY familiar with all aspects of the Climate Control system. The book really helped.  Some items just need to be cleaned, some pretty much don't break, and some age out over time. It appears that the two vacuum systems are partially working, but there are likely leaks. The components such as the transducer, controller appear to be working from your description. The mode door, power servo and 80/20 door might and their associated vacuum lines are the likely culprits for the current errors, in addition to the master switch being broken,

The Master Switch (aka steamboat) only energizes the fan relay. Without it connected, or mickey moused - No fan. The Power Servo in conjunction with the dash controller controls whether the fan operates at fixed LO or HI speeds or is modulated in AUTO or FOG. While I was having maddening vacuum leak issues I jumped the two master switches together. Result the fan ran at LO even while the system was off, but it's better than no fan at 110 degrees.

BTW, I have an original spare working clock.

[rustytractor]

Russell

Sent you a PM about the master switch.

Tim

I got your PM, I've just been tied up putting my '59 back together so have tucked the '68 away for a while.

I'd like to order one of your manuals but in digital format - do you have these available ? Although I love old cars I prefer the convenience of the digital world for manuals etc.

[cadillactim]

Russell

I don't have the manuals in digital format, only printed manuals.

Tim