1997 LeSabre heater problem

My Buick heater blows out warm air on the driver's side but cool and cold air on the passenger side. I have the automatic climate control. All the controls seem to work. The car heated properly during the winter, but now that the weather has been a little more moderate, I can't get the passenger side to heat. Could the right hand sensor on the dash be defective? Anything else I could check?

My Buick heater blows out warm air on the driver's side but cool and cold air on the passenger side. I have the automatic climate control. All the controls seem to work. The car heated properly during the winter, but now that the weather has been a little more moderate, I can't get the passenger side to heat. Could the right hand sensor on the dash be defective? Anything else I could check?

Take off the plastic hush panel under the passenger side of the dash. Take off the glovebox door if it's like my 98's where it has 5 screws along the bottom edge on the hinge.

You're looking for the heater box and the programmer box sitting at 45 deg angle on the corner. There's a white plastic arm sticking out of the heater box that is the arm to the vane for the passenger temp. That arm snaps onto a threaded rod that comes out of the programmer box that controls it. Yours may have unsnapped. It may be that the programmer box's electric motor isn't moving the arm.

You can turn the key to ON and operate the heater controls for the passenger and main heat. You can watch the lower white arm move and the little actuator electric motor on top of the heater box that moves the vane for the driver's temp.

If the arm is unsnapped, turn the settings to heat demand at 90 and wait for everything to move. Move the vane white plastic arm to heat, then snap it on.

http://i86.photobucket.com/albums/k110/imidazol97/HeaterCore1-1.jpg

At the top you see the white plastic arm for the driver temp.

At the bottom, near where the two wires are clipped to bottom of heater box, is a vertical opening and the passenger arm is there--it moves horizontally in and out, left to right.

The programmer box--the computer controller for the heat/AC is not on this picture that I found on the internet.

Thanks for your helpful response. I was able to open the glove door past the stops and see the control that directs the air flow. Everything was fastened so I removed the arm from the controller just to see if there was something jaming the vane. I switched on the ignition and saw the arm move. I reconnected it to the vane and now everything works fine with plenty of heat on the passenger side. This happened a few years ago during the winter and later the problem went away. I assume the motor or the controller is intermittant.
Thanks for directing me to the right area. I plan to keep "Dudley" (the '97 LeSabre) for a few more years yet so I will fix everything I can. I have the factory shop manuals.

Thanks for your helpful response. I was able to open the glove door past the stops and see the control that directs the air flow. Everything was fastened so I removed the arm from the controller just to see if there was something jaming the vane. I switched on the ignition and saw the arm move. I reconnected it to the vane and now everything works fine with plenty of heat on the passenger side. This happened a few years ago during the winter and later the problem went away. I assume the motor or the controller is intermittant.
Thanks for directing me to the right area. I plan to keep "Dudley" (the '97 LeSabre) for a few more years yet so I will fix everything I can. I have the factory shop manuals.

Thank you for coming back to tell others what you found. It will help them with their problems.

Did the white arm to the inside of the heater box move freely?

Maybe the thing just stuck... The programmer boxes are pretty popular from junkyards. A model number covers several years, so if the motors quit working it's fairly easy to remove 2 screws, 1 large connector, and one small connector to the actuator motor on top and replace the thing.

Yes, the arm to the heater box moved freely which makes me think the controller was intermittant and was the problem. My wife is happy now.

imidazol97:
Thought you might be interested to know that I finally made a trip to the junkyard as the heater controller was still intermittant. I had to find a LeSabre close to my year and remove the controller. Mine had only one connector. They charged me $15. I put it in and it works fine. I can't imagine what a GM dealer parts department would have charged me.