The fan on the climate control on my '84 300SD has started acting up since I had to have the compressor replaced and changed over to 134a last week. Before it worked fine, but now the fan won't start in heat mode unless I push the defrost button first. It also seems like that when the car finally gets to the set temperature that the fan shuts completely off and I hear one of the doors slam shut from underneath the dash( even with the ac on) . I seem to recall that it usually would go to low speed.
Last year I replaced the pushbutton unit because the thing would pour cold air out ....then the heat would come on full blast...then the AC would come on to try to regulate the temp...and so on. This seemed to correct the problem, but I wonder if it could be the problem again. It was a rebuilt unit which some people have told me is a no no with these cars.
Any help would be appreciated!