: 87 Brougham A/C problem

09-25-11, 05:57 AM
Newbie here. Yesterday, I bought a 1987 Brougham d'Elegance with 61K miles on it. I am trying figure out the climate control on it. I think it may have a problem.

I set the system to AUTO and the temp to 72. Outside temp was about 80 or so. The system turned on the fan and it ran consistently at high speed and was blowing cold, but then, would start blowing hot air. And, the fan speed never dropped...it just stayed at high speed (for about 30 minutes of driving or so). If I set the system to LOW, the fan speed would go to low, but the air will come out hot. I seemed to get the most success by setting the temp to AUTO and the temp to 65. It only blew out hot air a couple of times that way.

I traded my 2001 Park Avenue for this car, as it is in fantastic condition. Plus, I've had other cars with automatic climate control. My other cars never had a problem with the air going from hot to cold and back again.

Am I using this Cadillac's system wrong or is there a problem that I can fix?

Thanks in advance for your help.

09-25-11, 10:19 AM
Check the pressure in the system. Is it still R12 or has it been converted to R134a? The incorrect behaviour may be a programmer fault.

09-25-11, 12:28 PM
I don't believe that the car has been converted to R134a. When you say that the behavior is a programmer fault...does that refer to the ECC unit in the dash...or to something else? Sorry for my ignorance...I don't much about HVAC systems.

Another question...under the hood is a 3-wire connector on the passenger side, near the firewall and A/C components. It is disconnected and when I connect them, I hear a pump sound. Do you have any idea what that is for?


09-25-11, 12:55 PM
The system may be just low on freon.. With the setting on 80 degrees does the compresson clutch stay on and keep the compressor running? It should stay on most of the time.. If too low on freon it may not go on at all...
The three wire plug that is disconnected is for the power antena.. Yours must be broken..

09-25-11, 03:16 PM
Does the accumulator have a black or a blue cap on it?

09-25-11, 03:50 PM
Is the accumulator the silver can (looks like an oil filter with different ports coming out round it)? I believe that's what it is.

If so, there are several openings with black caps on them. I don't see any blue caps on anything that appears related to the A/C system.

And, I turned the A/C to 80 (and 90) and couldn't tell any difference between that and 60.

Yes, the antenna is broken...I'll have to get a new one and figure out how to replace it. Thanks for solving that mystery.

09-29-11, 03:22 PM
1st have the system checked with gauges to confirm its full. If full, remove the glove box inner liner (4 screws) if you look deep into the dash (upper left side) you will see a threaded rod attached to a white plastic arm exiting the top of the climate programmer. Start the car and change the display temp to 60 degrees, you should see this arm and rod slowly retract towards the firewall, then change to 90 degrees, the arm should slowly and smoothly move towards you to fully open the blend door on the heater core. If the movement is slow and smooth in both directions, you can gently pop the rod up and off the white retainer. With the system set to 90 degrees, pull hard on this rod to verify the door is fully open, then snap it back on. Also look at the black ribbed hose that goes to the in car temp sensor, make sure its not kinked or off at either end. You have now done everything you can do short of diagnosing and replacing components. Report back.

09-29-11, 10:31 PM
Thanks, Carnut...you saved me $$$!!!

I was planning to take the car to the A/C repair shop tomorrow to check the freon levels and the system as a whole...but I decided to check the control arm you talked about tonight. I took off the glove box liner and found the threaded rod...disconnected from the white clip. I checked the movement of the clip and it works very smoothly. I set it as you suggested and connected the rod to the clip. Now the A/C works perfectly.

A thousand thanks...and thanks to everyone who responded.


09-30-11, 01:53 AM
God! I love it when its simple!! You are welcome. I just bought another Cadillac myself. A 1984 Sedan DeVille with 95,000 miles. Looks 3 years old.