: 'allways hot'

joe joyner
04-16-05, 10:06 PM
My 81 deville's interior heater/eco/ac climate control always blasts hot air. I put in a new part which i think is called a modual box{6 inch long plastic box located under the hood passenger side-next to hood hinge} with no luck- still just hot air! Then someone told me to check if the clutch turns on the a/c thing conected to a fan belt like the altrenator- it does not turn. My a/c has no coolant, a leak i guess, which i will get repared as soon as i can find out why i can only get hot air now. i hope someone understand what im trying to describe? thanks:crying2: for your time joe

The Ape Man
04-17-05, 10:39 AM
Same system is used on '81 through '85 and maybe later. Common problem. 99 percent of the time your symptom is due to the following problem. Make sure that you see the failure before spending $ on any parts. This is an easy fix. Here is a very oversimplified description which will make sense when you get the tool set out. Under the dashboard is a black happy box which has a small threaded linkage that connects to the air mix door which directs air through or around the heater core. IIRC, you remove the glove compartment liner to access it. The box bolts right on to the heater box with 3 fasteners. There is a white molded plug near the bottom which contains 6 vacuum hoses. Also there is an electrical conector on the left hand lower portion which has 10 spade terminals and probably 11 wires. Inside the box is a small DC motor and gear gizmo. There is a lever at the top which has a white plastic clip which attaches to the threaded linkage which dissappears into the heater box. The failure is: the gears strip out and that leaves the air door stuck. First you have to find the box. Then run the car with the climate control set at 90. You will see the air door linkage start to move after 20-30 seconds to route all air through the heater core. Then set the climate control at 60 and check to see if the linkage moves the door in the other direction. My guess is that you will see a dead spot and maybe hear a faint clicking sound. The repair is to either get the motor and gear from the dealer (they might not carry this anymore) and install it inside your control box or get a whole happy box from the junkyard. If you cannot locate these parts then let me know. It is important to install the replacement part correctly or it can be ruined. Re-install the part without clipping the threaded rod on to the white plastic clip. Test the new box the same way as you tested the original to make sure the arm moves. After that, set the climate control back to 60 or 90 and observe the arm run to it's limit of travel. Now, push or pull the threaded rod which connects to the air door so that it's position matches that of the arm on your happy box. Pop the threaded rod into the clip and you are done.
One thing you want is a factory shop manual. Ebay has them. Priceless for anyone at any experience level who wants to maintain his/her automobile. If I had mine then I'd tell you exactly what Cadillac's name is for the happy box. Problem is that I loaned the manual out and it walked away.
Save your power module which you just changed. Throw it in the box in your trunk with the old fan belts that you keep for an emergency.

04-17-05, 09:38 PM
Well said The Ape Man (member.php?u=21874)

joe joyner
04-25-05, 01:02 PM
:drinker :drinker Cheers, ape man, someone up there likes me! Found a 81 coupe deville {same as me own} it runs, stuck in a garage the last four years, guy sprayed in a copper colour, didnt like it, all chrome stuck in trunk. cadlitic converter plugged i will cut it off when the sun comes out again, will get me cool air working now may even part the rest out. joe joyner
oh yeah, paid $500 cnd
wow wee !!!