Cadillac Repair: 1990 Cadillac DeVille / No AC or Heat air blowing, plastic vacuum, vacuum lines

Question
Hi. My question is my ac/heating is not working, there is no air blowing from the vents. The heater and the A/C are working but no air will flow out the vents. I have verified that the Fan Motor and Rat Cage are working correctly. I have also tried to attach a manual vacuum to the vacuum diaphragms under the dash and it made no different. With the A/C on and a Temp. gauge in the vent there is enough cool there for you to tell that the A/C is making cold air. It is just not blowing out of the vents properly. I don’t have much money right now to take it to auto a/c shop. Can you please help with this matter?

Thanks


Answer
Your most likely fault is either a loss of vacuum to the AC/Heater programmer  via the black plastic line located at the bottom of the programmer and or a faulty programmer.

Remove the glove box liner and the under dash panel on the passengers side so you can look up inside the dash and you will see a cluster of different colored plastic vacuum lines connected to a square plug which is held onto the programmer by a 7mm nut right in the center of the vacuum lines. Make sure you have vacuum on the black plastic vacuum line.

Also on top of the programmer you will see via the glove box opening a metal rod. as you switch your system from AC to HEAT this rod should move back and forth about 4" in a smooth manner and with no clicking sound.

I can provide you with pictures and diagnostic directives if you contact me at: onlineautohelp@msn.com