Heat..but no BLOWER! - PeachParts Mercedes-Benz Forum

dieseldaddy · #1 10-27-2002, 11:02 PM

1981 300TDT:
Symptom: Heat, but no blower. (A/C works great)

This summer when we used the A/C the blower worked great at all speeds. (low, auto, high)

Last winter the HEAT worked great as well. Now, we have heat barely trickling through the vents regardless of the blower setting.

Strange thing is that if I turn the dial to cold the blower will kick on just fine. Doesn't really help us for heat though.

I spent a fair amount of time yesterday attempting to diagnose and repair...but all I ended up doing is taking a lot of things off only to have to put them back together (dash related crap) with nothing to show for it but a couple bloody fingers.

So I have been online doing several searches for the last two hours HOPING that this is a very common problem and I can solve it with $0.37 rubber vacuum line and about 1/2 hour labor. (just kidding...but that DOES seem to apply to most of my repairs thus far!)

Well, nothing came up in my searches on the 123's but some things caught my attention:

1. Are there TWO SEPARATE blower motors for heat and A/C?
2. Does this appear to be a symptom of a bad monovalve?
3. What the heck is a "blower regulator switch" and does my car have one?
4. Yes, I have checked all fuses in the box...but are there other sneaky ones hidden somewhere?

Seems strange that this would be happening all of a sudden. Need help fairly quickly as old man winter is quickly approaching!
(Man, do I live in the wrong state or what?!)