Keep blowing Fuse 14
 

I am going to Las Vegas from Idaho and need a cool car. I will put a fuse in the 14 block and it seems to control the horn, key buzzer and valve that makes the A/C cold. Is there a way to run a direct hot wire to make that valve open for ac and bypass so it works. It is a 84 300D.

Replace the #14 fuse and avoid using the kick-down switch. Just a good guess.

More info
 

I have been toting with this problem and here is what I have figured out. The fuse is only blowing when I turn my dial to max Ac. If I let it blow anywhere else it works but if I turn it to lock it down to max Ac the fuse goes by by. Anyone had this issue before and know how to resolve it?

Your blower motor may be drawing too many amps at higher spped. If it's old there may be some restriction (crud, rust, worn parts). I just replaced mine as it was seizing up. may need a meter to see what's going on.

Not sure of the fuse box on your W123, I sold mine years ago, but check these:

http://www.peachparts.com/shopforum/diesel-discussion/253697-617-melts-fuse-11-1985-300sd-whats-scoop.html?highlight=fuse

http://www.peachparts.com/shopforum/diesel-discussion/253443-1985-300sd-617-aux-fan-c-thoughts-help-needed.html?highlight=fuse

Perhaps they have some insight to help you.