73 220d w115 Electrical HELP
 

Issues with no turn signals. Running light. Brake lights intermittent. All the bulbs are good, fuses are new... Cleaned the terminals in the fuse box as well. Still having probs

Maybe a bad ground somewhere??
Where are the grounds for the tail lights and side marker lamps.

Any suggestions on further troubleshooting? Thanks !!

On a car that old ground problems are pretty likely. I don't remember exactly where the ground points are, but on Mercedes brown is ground.

Yes, sounds like ground problems...
try taking a good sized wire and installing it from the neg post on the battery to the engine and the car frame...

Attachment 124118What are these relays used for?Attachment 124118

And this relay is for what also?

Not sure about the photos in post 4, but the picture in post 5 is the external voltage regulator for your alternator. More modern MBs have it integrated into the alternator itself, but on (some? all?) w115s, they have that external voltage regulator located on the left side of the engine compartment (as you are looking at the engine).

Never had a problem with my W115, but on my w123 I had no turn signal when the hazard switch was loose. Maybe that could be the turn signal problem.

I don't think that issue affects the 114/115.