Hello everyone!





My name is Shane and I am the new owner of a 1995 Lesabre Custom. Pretty nice car. Picked it up for 1900 and hopefully it''s problems are few. Anyway, the AC randomly goes to defrost no matter what setting it is in. Is the blend door vacuum controlled? I had a similar problem in a previous vehicle and it turned out to be a bad vacumm hose.





Thanks in advance for any help!

 

Hi Shane, my a/c does the same thing....find a solution yet?


Eric

 

Anyone have any suggestions?

 

Before replacing electronics check all vacuum lines, especially reservoir can/ball on L front of car.

 

For safety reasons, the climate control will default to defrost. Usually this indicates a vacuum leak.

 

Vacuum is likely the problem. The previous post is right about making sure vacuum hoses are on and NOT cracked or leaking. The rubber deteriorates and can crack and leak. Your year, I believe, has the vacuum storage tank for the heater (and cruise?) on the firewall right next to the box that says MaxiFuse Center or Relay center. On the bottom is a small connection for the vacuum line from the motor. Check both ends of that line.


Then the vacuum line goes to the inside of the car to provide vacuum for the little diaphragm motors that move the vanes inside the heater box. Check that line which goes to the passenger side.


The tube once inside the car can be found by taking off the plastic hush panel above the passenger''''s toes. It will have 2-3 screws and couple of flat metal taps holding it to the firewall above the carpet.


The incoming tube will probably be black and then connect to a violet tube. What often happens is that the tube at the controller that goes to the dash vents softens and sucks closed. The plastic deteriorates over years and with heat. You need to determine if your tube to the dash vent vane is getting vacuum or not. Over above the driver''''s toe is a tube that''''s blue, most likely, and moves a diaphragm that''''s moving an axle that''''s horizontal and goes left to right. That vane closes the defroster air flow and makes that air come out the dash vents for AC.


You can infer that this is the problem if you can move different buttons on the control and get vanes moving to make the air come out the floor, and the bilevel, and then defrost. That would mean you have vacuum inside the car; but check the items outside because weak vacuum may operate sometimes if there''''s a leak in the rubber tubes due to age.


No vacuum on the dash vent means you get defroster. No vacuum at all means you get defroster. So do a little troubleshooting. If you find the plastic connector is the problem, the income tube and outcoming tube can be connected with a short piece of aquarium line or 1/8 inch gas line.





Edited by: imidazol97