Climate Control Heater Blower Motor Won't Run A common problem on all models. Options for repairing it yourself and saving big $$$.
Climate Control Intermittent Cabin Heat - Second Generation Climate Control Applies to late 123 and 107 chassis and all 126 chassis 1981 to 1991
Climate Control Intermittent or No Cabin Heat - First Generation Climate Control No heat or heat all the time are common problems with 1977 to 1980 models with automatic controls
Climate Control Location and Replacement of Cabin Air Fitlers These really get neglected and they are easy DIY