1975 eldorado

[macdaddylong]

so i just got a 75 eldo conv
my past experience has been motorcycles and old ford trucks .so needless to say haven't done any heat or ac work
problem is neither heater or ac works . car in pretty good shape everything else except
1 clock
2.high beans flicker after 10 on

the dash controll seems to be in good shape

suggestions on where to begin my trouble shooting?
thanx

1949 harely flathead
1967 r60 bmw
1985 ram charger

[Scot Minesinger]

Welcome!  I have restored more than half a dozen climate control systems including two 1975 Cadillacs both FWD and RWD.

Buy the shop manual for a 1975 Cadillac, it is in two volumes a print of 1974 and the 1975 supplement (brown about 1/2" thick).
Buy Cadillac Tim's 1975 Cadillac Climate control repair manual (google him in Iva, SC).  It has a great trouble shooting section that gets to the route of the problem.

On 1975 Cadillac CC the most common problems in my experience are:

1.  The programmer behind glove box is bad
2.  The wiring connection to the programmer is bad and wires back out of the black connector and fail to make electrical contact (push them back in with needle nose pliers
3.  The VIR is bad (canister like device at passenger fire wall high with five refrigeration connections.  Watch out re-built ones have a bout a 40% success rate.
4.  Recommend a r134 conversion, as 12 is difficult to get now.
5.  Replace all under hood vacuum tubes one at a time, including the ones that go thru fire wall.

Of course you have to do your own trouble shooting.  Forget taking this to a standard shop my experience is they will butcher it worse than you can imagine.  I became my own best mechanic out of necessity, when I started out would just have written checks, but there is n o one I could find to do the work to my standards (fixing neatly and so it works).

Enjoy your Cadillac!

[bill06447]

so i just got a 75 eldo conv
my past experience has been motorcycles and old ford trucks .so needless to say haven't done any heat or ac work
problem is neither heater or ac works . car in pretty good shape everything else
suggestions on where to begin my trouble shooting?

Behind the alternator there is a temperature sensor that will not allow the system fan to come on until the coolant warms up a bit. First thing would be to pull the connector from the sensor and ground it to the engine and see if the fan works at that point. That should be the first step before getting all crazy, good luck

Bill

[TJ Hopland]

Most common place for headlight issue is the dimmer switch on the floor.   The carpet tends to trap moisture and things get corroded.  Look close at the plug because sometimes the connectors get corroded and can damage a new switch.

[Scot Minesinger]

Another cause for light flickering is a bad connection at alternator with two wire plug in.  The connector is on the flimsy side and re-crimping of female spades often improves things.

[macdaddylong]

Thanks guys for some help with this .gonna crank up some heat in the shop and try my luck with these suggestions

Last but not least any clock fix suggestions ? It work a bit here and there . I imagine there may be some stripped gear in there ?
Any ideas on clock fix ?

[Scot Minesinger]

The clock is no fun to remove on the 74-76 Cadillacs.  Two ways to fix it:

1.  replace it with a quartz action
2.  take it apart, clean it and re-lubricate with correct lubricant, that usually works, but not always. 

[macdaddylong]

So did some investigation today
When on HEAT  the bar moves all the way to heat but when you turn on ac it goes most of the way to ac but not all the way ..

When the ac is on the air comes out the floor but not dash vent

I have vacuum on black hose

No vacuum on black with white stripe hose

Where is ambient temp sensor ?

Where is vacuum actuator ?

Thanks in advance

[Scot Minesinger]

Ambient sensor is under hood near fire wall top passenger side.  It has a wire connector on it and the business part of the sensor is in the casing.  The shop manual and Tim's book show location with picture.  If the sensor wiring harness is pulled, then resistance in sensor array is infinite and that is recognized as too cold.  Jump the wire connector and it is no resistance that is recognized as too hot - bring on a/c.

The vacuum actuator is inside the programmer behind glove box.  If the actuator is not moving corretly it is usually the transducer in the programmer, never seen a bad actuator, but there is a first for everything.