300D,E proper fuses
 

Many newly acquired MB's or even long time owned have electrical gremlins.
A great number of these can be eliminated by just getting a proper fuse in the right clean fuse block location

Ceramic body fuses with copper/bronze fuse elements are sure the way to go.

Sets of these can be found on fleabay for a full fuse replacement with extras for around $10.

These can sure be a very easy way to improve your MB.

I go along with that!
Over time the fuse sockets and the contact caps can orrode, depending on the climate the vehicle is in.
I had for example, the A/C cabin fan cut out randomly. The cause, a corroded fuse!
While I had the fues box open, I removed the fuses and rplaced them with new ones, all of them!
Before reinserting the new ones, I applied a little dielectric grease to the contacts, after I gave them a short metal brush treatment.

Be careful with this stuff! Some years ago I made the mistake of buying this junk only to discover that the body of these fuses is not ceramic but plastic and the conductor is not copper/bronze but some cheap coated metal.

It's hard to find the real fuses wthout paying an arm and a leg, so whenever I'm at a wrecking yard I check for them on any German car. I always find some that are the real thing.