Cadillac Seville / Cadillac Eldorado Forum Discussion, 99 STS no heat through dash vents in Past Cadillac Vehicle Discussion; My 99 STS has heat to the floor and to the defroster, but none through the dash vents. I had ...
My 99 STS has heat to the floor and to the defroster, but none through the dash vents. I had a similar problem 2 years ago, but it was the floor that would not throw heat ($750 later all was well). I'd like to try a fix myself this time.
Just to clarify, you have no hot air through your dash vents when you set your a/c to blow through them (the man with the arrow pointing at his chest)? When the a/c blows heat in auto mode it blows the hot air to the floor and defroster always unless you manually adjust it (something I learned after an embarassing trip to the dealer). If it is not blowing when manually set I would say it is an actuator problem.
In cold weather with the system set to full auto, warm air should be coming mainly from the floor with some to the windshield and none from the dash vents. Add bright sun however (even in quite cold weather) and some air will come from the dash vents as well but it will be noticeably cooler.
Set the mode manually for air from the dash vents--if it works then it would seem that you have no problems.
i think the one you need is situated above the dabin air filters thats the a/c, def mode actuator it threw a B1344 in my 98 sts i have no defrost or ac,its the blend door part no. ac delco 15-72631, about $60.00 at oehq.com