1982 300TD - #8 fuse keeps blowing. It is for heater fan. When I bought the car I saw that it had a blue (25amp) fuse but fuse box cover called for a red (16amp), so I switched it to red. Then I started blowing red fuses. So I switched back to blue. Mistake?

Good question, too bad nobody's replied yet.
I have the same year/model car with the same situation.
The previous owner of my car had the a/c converted to the new, crappy refrigerant system (I think it's R134 or something) and I'm hoping that the shop that did the conversion upgraded the electrical system to handle the higher load allowed by the 25a fuse. I did the same thing as you, noticed the "wrong" amperage fuse in the #8 slot and when I replaced it, the fuse blew immediately. My fuse box also shows blackened, melted plastic right at that fuse, so there has obviously been some problems with that circuit in the past. This is always the down-side to buying used automobiles, you never know exactly what was done in the past.

__________________
Dave
1995 C280
1999 Triumph Daytona 955I - my speed fix.
1982 300TD - Gone, but not forgotten.

If the armiture or bearings start going bad in the heater motor you will blow that fuse.but look for a bad wire or bad switch first.....
william Rogers....

The AC was converted to a newer system before I purchased it, so perhaps it is the cause. Thanks for the pointer.

What was the fix for this? My 1987 300D has R-134a now. The condensor leaked a few months ago, i just got it fixed. now if I use the REgular mode (even for heat) it blows that fuse. If I select economy mode, I can run the blower until the cows come home. Once that fuse blows, I get natural HOT air...

Thanks,
Brian

When I first got the car back in August everything worked fine, with the red fuse. note that as part of the A/C condensor change, I also had the blower motor replaced. Is it possible the new one draws more current? Would seemt to draw less current. Old blower motor was replaced to stop intermittant noises as it was starting to go...

Brian