Heater problem on 1994 Cadillac DeVille

My 94 will blow hot air to the passenger side, but only luke warm to drivers side while parked, but when driving the drivers side gets only real cold air out like the outside air is coming through only. I pulled the glove box and manualy tied back the temp control arm to it's hottest postion. What do I do next so I get heat to the drivers side, "both at floor and windshield."

1 answer
Hi I have the same problem . The control arm is adjustable so adjust so it gets hot at 90 and see if it goes to max cold at 60 . Take the control arm and manually shift it back and forth to free it up first . Thats what I read in the gm manual on that car cause mine does the same thing drivers side cold passenger side 100 and rev the engine and some times 150 or more . But it should still change doors to def or floor with the dash controls I think just no heat to ac and maybe you might get heat out of the a/c vents buy putting it on econ and turn the temp down it will think its on ac but manually you have it on heat. The arm you tied back is max heat one way and max a/c the other way. or go to a you pull it salvage yard and get one there lot of devilles out there . but I don't think its a heater core . drivers side dosent get has hot as passanger I don't think hope this helps . i'll be working on mine again on 10/5/14 or last year I put tape over drivers side so my feet didn't freeze