AC Controller Under Dash 76 Eldorado

[davidmezz@me.com]

Hello.  I am in search of an AC controller for under the dash of my 76 eldorado.  The current one is shot.  I have a temp fix on there now by using a strong wire-tie to hold the switch/door open so that the cold air blows out the proper registers. If I don't use the wire-tie the cold air only blows out the lower vent where the heat normally comes out. 

If anyone can direct me to someone that sells a new or refurb controller that would be great.

Thank you,
David

[TJ Hopland]

You can usually find them but they don't come cheap, like in the $500 range. You probably want to do further troubleshooting to make sure its not being told to do the wrong thing or some other external issue.  You could spend that $500 and still have the same problems.   If it is an issue with the unit it may be cheaper to just replace what failed on it than the entire unit.

Did the temp change as you rotate the dial from 60 to 85?  Just always stayed at the floor?  Does the blower speed change when you are in auto and slowly rotate the dial?  You should be able to find the spot that is pretty close to ambient that it will slow down then if you move either direction it will speed up.

["Cadillac Kid" Greg Surfas 15364]

David,
I would check all the vacuum lines and the actuators first. If a vacuum line is broken or loose or the mode door actuator is not functional you will get the symptoms you described.
Greg Surfas

[davidmezz@me.com]

Thank you for the replies.  The temperature adjusts perfectly as I adjust the dial. And the blower speed also adjusts perfectly but all the air (cold, warm, or hot) all come out the floor vent. However, the only way I can get the air to blow our the upper registers is to use a wire-tie.  David

["Cadillac Kid" Greg Surfas 15364]

It sounds like your control head is functioning. I would repeat checking the vacuum lines and the actuators.
Greg Surfas

[TJ Hopland]

I'm with Greg, it sounds like the programmer is working. I don't know 76 specifically so maybe that has unique failure modes but in general in the era when the programmer fails it tends to do little to nothing. The fact that blower and temp changes means its mostly working.

Which thing do you have zip tied? I don't know what they called it then but later the which outlet selector was called the mode doors.  The programmer has a vacuum distributor thing in it that sends vacuum to the various vacuum servos.  Since the temp is working that indicates that there is vacuum to the programmer and its able to control the temp so the distributor is moving.  That kinda leaves a loose or bad vacuum line or a bad servo that operates that door.           

[V63]

Independently you could apply vacuum to the programmer and verify its function.

["Cadillac Kid" Greg Surfas 15364]

If the fan speed varies and the temperature at the outlet varies, the progrmmer must be receiving vacuum since that is what drives the mechanical components of the programmer.
Greg Surfas

[davidmezz@me.com]

Thank you.  To answer TJ, there is a little piece of metal.  I guess that is the "door."  If you wire tie that door it forces the cold air to the correct registers.  Without the wire tie the air only comes out the bottom vent near the floor.  I will look for those parts you guys mentioned above.