As stated in the title I'm having serious issues with my climate control on my 1984 Coupe Deville. It started when I heard a clicking sound underneath the passenger side of the dash almost like a relay clicking on and off. That day I when I went to turn the car off I noticed the heater fan didn't turn off so I had to manually unplug it from underneath the hood.

Since this has happened I have been plugging the fan in when I drive and unplug it when I park the car. I did notice the heat seems to be always on full, both temp and speed as it seems the controls are no longer controlling the system with the exception of the 2 defrost buttons. I tried a different controller from another car but it did not fix the problem.

I got under the dash and looks like everything is plugged in but did notice it sounds like there is some kind of motor constantly turning somewhere in that area when the key is on.

Has anyone had this problem or know what I should be looking for to fix it? Any help would be greatly appreciated as its getting colder outside and having working heat would be great!!!

I too have something that clicks whenever the Climate Head is on AUTO. I've always wonder what it is. I can even hear it in the engine bay, over the engine.

Remove the glove box liner, you will see a metal rod that is snappped into a plastic arm on top of a black plastic box. Inside that box (climate control programmer) is a DC motor that moves that rod to open or close the heater case blend door. Over the years of use the DC motor breaks the plastic drive gear, so as it trys to move to maintain cabin temp it slips on the broken gear and ticks and ticks and ticks until you move the temperature display up or down. Bottom line, the programmer needs replaced. Or if you are a better than average mechanic, you can remove the programmer and replace the motor inside it from any large wrecked GM car with auto temp climate control. ( cannt buy the little motor by itself) Once replaced, hook up everything to it but the metal rod.
Run the temp to 90 degrees, car running, wait a min. then pull the rod towards you and reconnect the rod to the plastic arm. That adjusts the blend door. That should fix the fan as well. If the fan still runs with key off you need the fan power module, as well, that sits in the HVAC box above the blower motor under the hood. Most times this programmer motor fails because some people think the heat/cool system is like a Chevy. They constantly move the temp from 90 to 60 which causes this little motor to have to move quickly to either extreme, eventually breaking this plastic gear. My 84 is set to 75 degrees and auto 360 days a year and will warm the car in the winter and cool it in the summer. On a nice evening, moonroof open I reach over and touch the low button.

That does seem to be my problem. My motor still works but I can see where it it gets stuck and starts to click. You were talking about replacing the motor, since mine seems to work fine is there anyway to repair the gears inside?

A different thing I noticed, right beside my main engine computer there seems to be a map sensor. Mine currently has no vacuum line attached to its nipple, is there supposed to be something attached to it?

attached to its nipple, is there supposed to be something attached to it?

Don't attach anything to your nipples, it hurts! :crying2:

just playing :P

No, just replace the motor inside the programmer. Once you have it on the bench, you'll see how easy it is. Regarding your MAP sensor, if the hose was off, missing, the car would perform badly and have a service engine now light on all the time. I think you're looking at the fresh air vacuum diaphram. If so, yes there should be a hose attached. If you are willing to work on this car, you need the factory service manual first.

does this programmer also control the direction of the air? My air only comes out the floor, heat or AC.

does this programmer also control the direction of the air? My air only comes out the floor, heat or AC.

That's controlled by vacuum. If the car your talking about has the 307, then there is a vacuum canister mounted to the passenger side of the fire wall. It looks like a black ball. Make sure the vacuum line is connected.

it has the chevy 350

Yes the programmer controls air flow if the stored vacuum is sent from the storage canister. Check what SVEN914 says and if vacuum is present then suspect the programmer. The vacuum harness is bolted to the bottom of it and rarely comes off.

Mom's 84 is experiencing HVAC problems, too. Sometimes, the display buttons don't respond. And, it seems that it will only blow cold air. I'm ready to replace the display and the programmer, but I wonder if the symptoms point to programmer only? I know the display interchanges from 82 to 85. I wonder if the programmer from later years will work...

we tried the 90 display in an 87, it plugs in but didnt work so I know the 90 doesnt work for other years

The display module is the main computer for the HVAC system. When buttons dont respond it needs replaced. The only difference among those years is whether it has a rear window defog button or not. I presume you've taken the glove box out and watched the blend door metal rod move when 90 degrees then 60 degrees is selected? If the rod moves jerky or stops for a second then moves, you need the programmer as well. The display is also the main diagnostic display for the ECM system. If some buttons dont light up, then a proper diagnosis of driveability and various sensors cannot be done.

That's what I figured. I can still get it to move the blend door. I can also get into the diagnostics. It does have the rear defog, even though it was an FL car. When off, it is very reluctant to make the switch to Econ, low, auto, or hi. Same when trying to go from one to the other.

I'll grab a display module for it. Should be cheap used, but they are available rebuilt through AC Delco. You can see the PN on the box. Also, STANDARD MOTOR PRODUCTS Part # ECC8.

http://i40.photobucket.com/albums/e202/jayoldschool/CadillacHVAC.jpg

If the programmer rod moves then maybe a problem with the hot water vacuum valve in the heater hose under hood. At 60 degrees displayed and in auto, NO coolant goes to the heater core. Vacuum keeps the heater valve shut. Any temp above 60, full vacuum is taken away by the programmer and opens this valve. With a friend behind the wheel and you watching the valve, you should should see the little rod on the valve move back and forth open to shut as he moves the display from 60 to 65. If it does then verify the hose is hot on both sides of the valve by feel. If the back side is cool, the valve is broken inside keeping coolant from the core.

Thanks, I will check that, too. I'm leaning towards the display since it won't respond to button selections. I just missed one on ebay. However, mom is headed to the winter place in FL, so she can hit the U Pull It!