Heating issue

[72caddy]

Hello, I just got a 72 Fleetwood. My a/c works fine but the heat never comes out hot and the air never goes out floor vent except when the setting is on bilevel. No matter how warm the engine is, I never get warm air even from defrost. All vents work except the floor vent except on bilevel as I said and no air ever comes out warm. A couple of times I started the car with temp on 85 and air came out on floor but it never warmed up. Also when this happened, as the engine heated up the vent switched to a/c vents. Also, engine temp light is always on even when car is cold. Can all this be connected? Can anyone help?

[cadillactim]

Might have bad transducer or vacuum leak in programmer not allowing system to go to full heat. Not related to engine temp light.

Tim

[Scot Minesinger]

The climate control measures outside air temperature, interior temperature and discharge air temperature.  If it is summer, it may not let you put the heat on.  Conversly, it will not let you have ac if it is 20'F outside.  Your system could be malfunctioning, but if the ac works, that really points to a well sorted mechanical condition. 

If you have not already, buy the following manuals:

1.  Factory Cadillac shop manual for 1972
2.  Body by Fisher body manual for 1972
3.  Cadillac Tim's book on climate control, it is very helpful.

The first two books are on e-bay for low cost (like $40 each), and google Cadillac Tim in Iva, SC to buy his book.

These are worth their weight in gold.

Enjoy your Cadillac!

["Cadillac Kid" Greg Surfas 15364]

Russel,
Your problem could be several things or a combination of them, but since you said when you start the car with the temperature dial on 85 and you DO get a continuous flow of air out the lower outlet I would first look for either a closed shut off valve in the heater water circuit or a bad heater control valve.  It is also possible that someone installed the wrong heater water control valve in the car.
The factory service manuals are invaluable for diagnosis and particularly for determining if all your components are correctly installed.
I have both a 75 and a 76 and find essentially no difference in the vacuum circuitry between the two.
Greg Surfas