1975 w115 300d Glow Plug Relay Fuse Location?
 

Is there a fuse for the glow plug relay on a 1975 w115 300d? Anyone know? Thanks!

There is no fuse on that car. The relay has a overload protection circuit that trips if it draws to much current.

So how is it reset? I saw a little silver box with a rubber button on driver side inner fender well that can be pushed in -this must be reset button?

No the relay will reset itself every time you turn the ignition key off.

The button under the hood has nothing to do with the GP system.

The glow plug relay on my 1975 W115 300D is behind the kick panel under the steering column, over near the ignition switch. It is either white or gray (cant recall) and it clips onto something under there. Sorry I cant be more specific, but it has been over 10 years since replaced it.

I hooked up a DMM to power supply and turned on key and saw not volt readings -guessing that my indie fried my relay when he hooked up a charging unit to battery leads to power up a window that was down without the ground strap connected to anything . . . . . zap! Prior to this, the fast glow system worked great!

so what is that little switch for with the rubber button -it acts like a reset/overload button when you push it????