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1970 Climate Control - Blower Speeds

Started by Dan LeBlanc, November 08, 2016, 08:33:25 AM

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Dan LeBlanc

It seems as if most of the climate control is functioning as it should (heat and cool, positions where they should be, when they should be there) with one exception.

In Auto Low - Auto - and Auto Hi, the blower seems to maintain one speed (low).  If I move the lever to FOG or ICE, I get maximum blower speed as I should.

Is it new dash unit time?  I don't have Cadillac Tim's book yet, so bear with me.  It's on the "to buy" list.
Dan LeBlanc
1977 Lincoln Continental Town Car

"Cadillac Kid" Greg Surfas 15364

Dan,
The first thing I would check would be the blower relay connections and the relay itself.
Greg Surfas
Cadillac Kid-Greg Surfas
Director Modified Chapter CLC
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-

Dan LeBlanc

#2
Is there only one relay on the car?  On the heater/evaporator case on the firewall just below the vacuum unit with the 4 or 5 hoses coming out of it?
Dan LeBlanc
1977 Lincoln Continental Town Car

"Cadillac Kid" Greg Surfas 15364

I believe they did not start using two until 1971, so you should find only one there. 
Cadillac Kid-Greg Surfas
Director Modified Chapter CLC
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-

Dan LeBlanc

#4
Relay does appear original, so it wouldn't surprise me if it has failed.

From what I gather, FOG and ICE send voltage direct to the fan, but auto doesn't quite work that way?  Although, one would think Auto HI would do the same as fog and ice?
Dan LeBlanc
1977 Lincoln Continental Town Car

"Cadillac Kid" Greg Surfas 15364

Dan,
Over the years they tried a couple of strategies for "high" fan circuitry.
I would check the connector at the fan relay first.  It seems to be a weak link on just about all versions of the circuitry.
Greg Surfas
Cadillac Kid-Greg Surfas
Director Modified Chapter CLC
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-

Scot Minesinger

Agree with Greg, this same thing happened to me and it was connections at relay.
Fairfax Station, VA  22039 (Washington DC Sub)
1970 Cadillac DeVille Convertible
1970 Cadillac Sedan DeVille
1970 four door Convertible w/Cadillac Warranty

Dan LeBlanc

Wouldn't hurt to clean the connections then 
Dan LeBlanc
1977 Lincoln Continental Town Car

Dan LeBlanc

Cleaned the contacts. All is good.

Now on to solving the rough idle issue and hooking up the ported vacuum switches and all that stuff.
Dan LeBlanc
1977 Lincoln Continental Town Car

76eldo

I see you are not wasting any time sorting things out.
Sounds like you will have this car perfect in no time.

Nice work!
Brian Rachlin
Huntingdon Valley, Pa
I prefer email's not PM's rachlin@comcast.net

1960 62 Series Conv with Factory Tri Power
1970 DeVille Conv
1970 Eldo
1970 Caribu (?) "The Cadmino"
1973 Eldorado Conv Pace Car
1976 Eldorado Conv
1980 Eldorado H & E Conv
1993 Allante with Hardtop (X2)
2008 DTS
2012 CTS Coupe
2017 XT
1956 Thunderbird
1966 Olds Toronado

Dan LeBlanc

Stuff like that keeps me awake at night; sooner I tackle it, sooner I can sleep.

Dan LeBlanc
1977 Lincoln Continental Town Car

The Tassie Devil(le)

Do you have to retain the anti Pollution Controls up there?

If not, route the Distributor Vacuum Advance direct to full Manifold Vacuum.

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
'02 VX Series II Holden Commodore SS Sedan
(Past President Modified Chapter)

Past Cars of significance - to me
1935 Ford 3 Window Coupe
1936 Ford 5 Window Coupe
1937 Chevrolet Sports Coupe
1955 Chevrolet Convertible
1959 Ford Fairlane Ranch Wagon
1960 Cadillac CDV
1972 Cadillac Eldorado Coupe

Dan LeBlanc

No emissions testing here.  I just like having everything hooked up and working as designed.

Right now the vacuum break switch is capped off as is the ported vacuum switch. Distributor advance is hooked to ported vacuum.

The vacuum diagram I downloaded here though shows three vacuum connections on the back of the carburetor and I only see two. There's the one the brake booster is connected to, one above that that's currently capped off (assuming this is where the modulator valve connects). There's something coming out of the carb above that not capped off but could be a port, but I'm not sure.

I'll have to snap a photo when I get to the hose replacement.
Dan LeBlanc
1977 Lincoln Continental Town Car

Jeff Rosansky CLC #28373

Dead center top back of the carb is the port that goes to the aircleaner.... at least that is how mine is.
In the future, don't discount the relay. I put a new one on a couple years ago and it already failed.
AT least the other functions are working. I still have issues with mine.
Good luck
Jeff
Jeff Rosansky
CLC #28373
1970 Coupe DeVille (Big Red)
1955 Series 62 (Baby Blue)
Dad's new 1979 Coupe DeVille

Dan LeBlanc

Thanks Jeff!  I was wondering what that port was for or if it was a vent. 
Dan LeBlanc
1977 Lincoln Continental Town Car

Scot Minesinger

The top one on back of carb does not go to the air cleaner.  It is connected to the solenoid switch on intake manifold.  It is a vent connection.  I have a Cadillac Factory published comprehensive vacuum diagram that is like a poster I can send you.  e-mail me your address and will mail one out.  The shop manual has this info in pieces and you have to be a detective to put it together.  Then in 1973 or so the shop manual starting including a comprehensive fold out diagram at back of shop manual. 

Dan, I have a 37k miles 1970 SDV hooked up with all vacuum lines correct and it idles smooth.  Also have a re-built engine 1970 DVC with 40k miles on the rebuild and have connected the dist advance direct to ported vacuum.  The vacuum solenoid and ported vacuum switch are there with dummy hoses to fake authenticity.  This also idles smooth, but with a performance intake (stock intake manifold re-machined on inside by MTS) and dual exhausts, it is faster and sounds better.  With stock set up you have to hit the gas hard enough to activate kick down switch on throttle to by-pass pollution control solenoid that allows ported vacuum to dist. in 1st and 2nd gear.
Fairfax Station, VA  22039 (Washington DC Sub)
1970 Cadillac DeVille Convertible
1970 Cadillac Sedan DeVille
1970 four door Convertible w/Cadillac Warranty

cadillacmike68

#16
It's your LO-AUTO switch on the back of the control unit (in the dash). They can be cleaned. Tim's book will help, but it's fairly easy to disassemble and clean - once you can get the unit out of the dash!
OK so it wasn't the LO-Auto switch. That could be a source of future issues if its contacts get dirty.  Primary symptom is fixed low speed on Auto, but goes to high speed on HI.
Regards,
"Cadillac" Mike

Dan LeBlanc

#17
Here's where I'm at with the rough idle.  Still haven't tackled the intake manifold gasket and I'm not sure I have to. I was tinkering around last night and could faintly hear an arcing noise on the drivers side. So, lights out and out came the sprayer. The almost new AC Delco wires were arcing all over the place (#4 cylinder to the air cleaner near the manifold, one between a wire and compressor - not sure which cylinder, some cross firing between wires at the cap, and a bit at the coil).  I happened to have a set of new wires Sixfins  (Art) gave me to get me out of a pinch in the drawer of my toolbox and put those on. It's very smooth now with a very occasional pffft. The vacuum gage is very steady at idle now at about 21".

Moral of the story - just because something looks new doesn't mean it isn't bad.

And - blower is still working at all speeds now. Funny what dirty relay contacts will do.

Did the shop manual electrical tests on the cruise control last night and found excessive resistance at the transducer. I bought a good used setup on eBay last week and will pop that in over the weekend.  If someone has a photo of how the chain attaches at the carburetor it would be greatly appreciated as mine is missing.
Dan LeBlanc
1977 Lincoln Continental Town Car

Jeff Rosansky CLC #28373

So the air cleaner vac line doesn't connect to the top back of the carb?
Screwdriver pointing to it.
Jeff

Darn, just pretend it's rotated 90 degrees.
Jeff Rosansky
CLC #28373
1970 Coupe DeVille (Big Red)
1955 Series 62 (Baby Blue)
Dad's new 1979 Coupe DeVille

Dan LeBlanc

Dan LeBlanc
1977 Lincoln Continental Town Car