climate control gone haywire
 

Allright, the weather's changed and it was time to turn the heat up tonight. So I did. first thing I smelled was a funny smell but i rolled down the windows and after a while it went away. the heater was burning hot air just fine but still with a bit of funny smell. no biggie. i figured it had been a while since the heater was used so it'll go away. but then I tried to turn the heat down a bit and I realized the climate control wasn't really working right. To double check I turned the control all the way to the coldest level.. but the vent kept giving luke warm air, the center vents never opened up which they do for cold air. and after a lot of tries it seems it's just not working.
so at this point, where do I start ... ?
it's my 87 260E about 119K miles.
thanks everyone !

You did not mention if the air comes out of the vents where you direct it to go?

It may be that the diaphrams on the cells/modules that control the heat/cols aire mixture is shot. Or it could one of the modules behind the dash. On my 190 there are three behind the dash and one underneath the wiperblade motor. If these are not in proper working order, the outside/heat/cold air mixture is all mixed together and the air does not come out where you direct it to come out of on the climate control panel. Which could also be part of the problem or even the AC relay.