1982 W126 300 Sd Ac/blower Fuse
 

I have this problem with the blower motor on my 82 300SD,it
keeps blowing fuses on weekly basis,now when I replaced the
last one blower stopped working after 1 min.,fuse did not blow
anymore.I took the dash apart,nobody touched it for 22 years and
there is no power coming to the blower motor at all(fuse is OK,climate control is fine),I used a wire to check the blower and
it works fine(worked for 1 hour,without blowing the fuse,smaller
size,from the radio,thats where the wire came from),any ideas,
AC compressor is disconected to make shure the problem is not from there...

blower motor fuse
 

You might want to see if some previous owner had the "external blower motor fuse" modification done.

I think you car was a W126, right? Older W126's had one fuse in the fuse box for the ACC control, plus another fuse in the fuse box for the blower motor itself. (I believe these were fuses #5 and #16, respectively.)

But, due to the blower motor repeatedly blowing its fuse, sometime during the W126 production run, they got rid of fuse 16 inside the fuse box, and replaced it with a separate, 30A or so fusible link, mounted in a little plastic box that is just in front of the brake master cylinder.

I don't know when this design change was made in production - my 1991 420SEL has it, but it is of course near the very end of W126 production.

Your 1982 presumably had the original fuse layout, but upgrading to the new fuse arrangement was a common "upgrade" done to many older cars.

However, even the new 30A separate fuse often develops hair-line cracks in it, leading to intermittent blower action, and then total lack of air. If you open up the little black fuse holder box (it is about 1" by 2" rectangular box, with a lead coming out of each end, just in front of the brake master cylinder, you can unscrew the little metal strip.

Sorry if this is unrelated to your problem!

Bob Schleicher
bullswin5@aol.com

My 1986 300SDL still has both fuses inside the main fuse box. I believe one reason they moved the b/motor fuse was it was heating up and melting the plastic around the fuse contact tab because of people leaving the fan on high. I've not noticed any extreme heat when I've checked it but that's probably due to me having it on auto all the time.