We have a 1995 C220 that has an irritating issue that I cannot track. Sometimes the blinker will not work and i noticed that the rear defrost works and doesn't work at the same time.

Anyone know of a relay or fuse or whatever that covers both of these that could be a problem? Thank you!

 

Sounds as thou you might have a relay problem. Or a connections ie socket has become rusted, and is shorting out the lights now and then. Clean with a Q tip and some alcohol the sockets for the directonals and see if the problem goes away. If not the relay I believe is located inside the dash. I would bet on the socket or a loose wire, relays work or they don't work, simple electonics parts but vital parts of the electrical system.
The rear defogger could be a loose connection, if it is at the window itseself, then the trim pieces will have to come off. The relay for the defogger is or should be located in the fuse box. While you are at it, check the fuse for each function to see if they are corroded. If non of these suggestions work then it is off to the dealer.

Mercedes are known to have cheap sockets, I have had problems with my brake lights. I disconnected the battery and cleaned the socket and then bent the prongs up so they make better contact with the bulbs. Now that I think about it try this first and see what happens.
Let us know how you make out. A word of advice when you are fooling around with these parts disconnect the battery as you could burn out or blow fuses and in extreme cases the cars computer.

If you have a moment, check out the Harley I just bought. go to my photo album, that is click on the camera icon below my name.