several months ago something went wrong with the heating / cooling system in my cars cabin...it seems as though something may be wrong in the air delivery duct system....in the heating mode, the engine is making hot air but air barely comes out of the duct system...in the a/c mode, cold air comes out of the drivers side dash vent at a reduced rate and the rate of air movement from the rest of the dash vents is even more reduced.
problems with heating / cooling system on 1994 Lexus SC400
by millerman in Las Cruces, NM on May 13, 2010
ANSWER by dandd on May 14, 2010
It sounds like your Climate Control System needs to be diagnosis, this system has its own computer and codes. here are some shops http://repairpal.com/directory?address=88001&car_brand_names=Lexus