Cadillac Repair: 1989 Cadillac STS Heater, coolant temp, cadillac sts

Question
QUESTION: I went past my follow up availability. I have problems with my cabin heat in my Cadillac. I replaced the water pump after it went out dramatically. Before and since this repair I was experiencing problems with heat. The programmer is working properly and all tests in the maintenance mode seem to be good. I do have an intermittant coolant fan fault happens when I slow and participate in city driving; this seems to spur the system to blow cool air. By the time I get out of the car and raise the hood the fans are working and the coolant temp has normalized. The heat does not return until I get the car on the highway. I am puzzled.

ANSWER: What codes are you getting from the computer caused by the cooling fan fault or how do you know you have a coolant fan fault ?.

---------- FOLLOW-UP ----------

QUESTION: The information area gives a "Coolant Fan Fault" message and when I go into the maintenance menu it gives me a B441 fault. I have cleaned the connectors on the fans and the control module and the fan fault has not returned on my last two test drives. But, the same thing with the heater is happening. When Im cruising it is just adequate, when I slow and sit the heater blows cold air.

Answer
If your POSITIVE that the programmer arm is staying in the maximum heating position which is all the way towards you this sounds like a restriction in the heater core which will need to be replaced. A very common problem. If you could physically feel the heater core you would feel it hot at the top and cooler in the middle and cold at the bottom.