Electrical problem/short?
 

I have a 1995 S600 coupe with a factory telephone that is randomly loosing power. It will even "blink" with the turn signal when making a right hand turn. The power goes on and off with the blinking of the lights, and afterward just shuts off. The turn signals work properly and the ground wire in the trunk by the left turn signal was just checked by the dealer and they said it was fine. They want to wait until it fails totally. I do not like to wait when it concerns electrical connections. A bad short can cause major problems.

Another shop told me to check the ralay for the turn signals. Apparently it also controls the phone? None of this makes any sense to me.

Any tips will be greatly appreciated.