Adjusting climate control dial - 1970 deville

[Dan LeBlanc]

I see there's a procedure for adjusting the dial in the FSM for adjusting the climate control dial.  Looks like there's a special tool used.  Is there a way to adjust without the special tool?

[Scot Minesinger]

Dan,

Cadillac Tim will know.  Thought I knew just about everything for a 1970 Cadillac, but cannot answer, as never has temp wheel been out of calibration on any 1969/70 Cadillac I worked on.

[Dan LeBlanc]

One of the items on the work order from the previous owner was replacing the climate control head.  It appears as if they also installed relays for the various blower speeds (didn't cut or splice any wires to do so, just tapped into the factory plugs).  So, the climate control head appears to be just a switch at this point and the actual current passes through the relays.  Pretty clever, I think.

I had the car out tonight, and it worked well.  It was about 65F here, so not warm enough to test fully.  Climate control goes to heat and cool as directed though (cools when I REALLY heat up the inside of the car to trick it into thinking it's hot out).  If I need to adjust the dial when the hotter weather comes, I'd like to know that I can.  Refrigerant lines frost up nicely under the hood though.  System was serviced in 2013 and seems to still be holding its charge.

Idle is much improved (haven't changed the intake gasket as vacuum is strong and steady).  When I got it, timing and dwell was off and after dialing that in, the lumpy idle is only slightly present.  Almost perfect.  The carburetor was rebuilt by Holley, and we know about the mass rebuilders . . . I may pull it and send it to a good Rochester rebuilder for a going through next winter.  It does seem though, that the more I drive it, the better it runs.

I do have to order a new cruise control transducer.  Mine is sticking when it accelerates up a hill (won't let off).  For the $90 O'Reilly wants for a remanufactured unit with warranty, doesn't seem worth it to mess around with the old one.  Plus it can be swapped out in less than 10 minutes.  After all, it is old, so might as well replace it.

That just leaves the clock and an oil change.  Top off the other fluids, and I should be good to go.

[Jeff Rosansky CLC #28373]

Ahhhh, a new climate control head sure would be nice. Maybe Santa will bring me one in 2017. Last year I just got socks and Fruit of the Looms-- Not the soft kind either.
For now I just do it manually but it sure is a pain.
Don't forget you can adjust the temp on the power servo to heater door arm. It may be easier than trying to adjust the dial.
If you have any parts left over in your garage trashcan, let me know!!
Wouldn't mind knowing how they wired yours tho.
I just put a quartz unit in my clock housing. Works well enough, $10.
Jeff

[Scot Minesinger]

Dan,

Cadillac Tim rebuilds the dash unit, so you can get a working unit.  The dash unit has a transducer built in that modulates vacuum output to servo at top center of firewall under hood.  The transducer usually is the weak link in dash unit.  If the unit switches over from heat to cool (hot air out floor vents, then cool air from dash vents) then transducer is working.  The power servo also switches fan speeds by vacuum signal, so if you ever replace any component, you will have to make sure the splices are accounted for. 

Used transducers are used to rebuild these dash units and I found they do not last.  If ever I rebuild a 1969 or 1970 climate control I use a divorced transducer from a 64-68 Cadillac which are re-buildable and abandon the transducer in dash unit (has a detachable plug, so easy to do).  The 1969/70 dash units are extremely difficult to remove and install - do not think of omitting the top screws or the bottom plastic mounts will break off.  Have not lost a 64-68 transducer yet, but if I do it is easy to replace, and I keep a spare.

["Cadillac Kid" Greg Surfas 15364]

Dan
To answer your question regarding the tool; what you need is something to hold the little (and fragile) toothed gear that is above the temperature dial on the same shaft.  What I use is a hack saw blade that I cut to a point.  Works perfectly.  The FSM describes the simple adjustment.
I have a question regarding the relays you see installed.  Speed control is normally via the resistors that are part of the power servo. I have seen (and done myself) a relay used to shunt current around the flimsy electrical contacts of the Master switch or the "upgrade" to using the later circuitry of using a "low" relay and an "auto" relay.
Interested in what was actually done to modify yours.
I have had great luck with the cruise transducers from Rock Auto.  I have over 20 years use on the one in my '76.
Check out the AC wiring and let us know.
Greg Surfas

[EAM 17806]

Dan,

Cadillac Tim will know.  Thought I knew just about everything for a 1970 Cadillac, but cannot answer, as never has temp wheel been out of calibration on any 1969/70 Cadillac I worked on.

SCOT:  Do you know Cadillac Tim's new web-site address?; if so, could you let us all know what it is.  I know it has been changed.   EAM

[Dan LeBlanc]

Thanks Greg.  I did find an Oldsmobile FSM section online that said if the tool wasn't available to use the corner of a steel ruler to hold the gear. I tried it and it seemed to work also. I want 70 on the dial to feel like 65 (I've essentially set my dial 5 degrees cooler).  It actually seems more accurate now. I haven't verified with a thermometer, but the feel like temperature in the car with the new setting feels right. I'm more about the feel like temperature than the accuracy. If it's not quite right, I can easily go back to where it was before.

From what I can see, there are 2 relays installed. The plug at the climate control head and the dash harness installed disconnected. There is some wiring tapped into both ends of the plug routed through the two relays. I didn't want to disturb things when I had the lower panel dropped to send out the instrument cluster for calibration because it's working so I didn't do much tracing.

I ordered the remanufactured cruise transducer this morning from Rock Auto. Haven't decided if I'll send the core back or not (I have two that are dead actually) or throw them on eBay in case someone is looking for rebuild able units. I have a feeling return shipping from Canada will exceed the core value.

Now to tackle the clock. My coils are shorted out. Movement is good.

["Cadillac Kid" Greg Surfas 15364]

Dan,
Do you still have the "master switch" in the circuit?
Greg Surfas

[Dan LeBlanc]

Is the master switch the one that turns on the climate control based on engine temperature?

["Cadillac Kid" Greg Surfas 15364]

Indirectly  yes.  It is also called the "steamboat" switch because of its appearance.  There are 4 vacuum nipples and 2 electrical connections.  On a 70 when the water temperature rises enough to open the vacuum port to allow vacuum to the master switch the switch contacts close energizing the electrical circuit.
Greg Surfas

[Dan LeBlanc]

I believe the steamboat switch in 69/70 is an Eldorado only item. The rest of the line had just an electrical switch near the alternator that energized the system when coolant temp reached 90F (at least that's what I gather from the FSM)

Whatever switch I have is there and working. I only have climate control when the engine starts to warm up (I'm thinking ICE on the climate control overrides that)   

[Scot Minesinger]

The steam boat master switch with four vacuum lines was last used on the RWD 1968 Cadillacs, and it may have continued on Eldorado as Dan writes.  The 1970 Cadillac has the dash unit with integral transducer, a remote vacuum relay under dash for defrost, and a power servo to provide climate control, aside from of course the three essential sensors, clutch solenoid, and heater valve.  The fan runs when ignition is on even if climate control is off.

["Cadillac Kid" Greg Surfas 15364]

That's strange.  My 70 (bought new by my mother) had a master switch in the. Ircuitry. I know because I still have the tree extras I bought for it when they seemed to go out  regularly.
GregSurfas

[cadillacmike68]

Is the master switch the one that turns on the climate control based on engine temperature?

No more Master Switch, aka steamboat switch on 1969 and later unless its an Eldorado and then only 1969-1970.

You just slide a knife blade, hacksaw (I use a letter opener) in to hold the teeth still while you make small adjustments to the dial. If you prefer it a little warmer or cooler, you can adjust it the way you want it. I have mine so that 75 is pretty comforrtable all year long, and a little nudge in one direction or the other gets thing a changin'

The control units can be gotten cheaply on fleabay, but you won't know their condition. Tim  can rebuild one as can classic auto air in Tampa FL.

With 1968s being much more complicated I have nearly a 100% duplicate / spare parts list including 3 spare control units for my car. I even have a spare condenser (the car's original one), but no extra compressor, those can be gotten anywhere in a day or two.  If mine seizes, I carry a pair or 48" bypass belts, which will also work in your 1970. In fact my engine has the same belt / pulley arrangement as your 1970.

[cadillacmike68]

That's strange.  My 70 (bought new by my mother) had a master switch in the. Ircuitry. I know because I still have the tree extras I bought for it when they seemed to go out  regularly.
GregSurfas

Greg, was it an ElDorado? According to the manuals, that's the only model with the steamboat switch. My 1970 Fleetwood Brougham built in Dec 1969 didn't use one.

[cadillacmike68]

Is the master switch the one that turns on the climate control based on engine temperature?

No. That's called the "ambient switch" and it is located on or next to the 80/20 recirculated air door in the bottom right of the front passenger area. That switch prevents system turn-on when conditions call for heat and the coolant temp is less than 100F. Unless you slide it to Def, De-Ice - DeFog, Defrost, etc.


Climate Control was always 100% fresh air unless on "HI" and on some years "DE-ICE". Then it was 80% recirculated air, hence the name 80/20 door. There are logical reasons for this.