Call this guy.

He is the install guru for mercedes benz cars.

It is his life and he will walk you through all of your electrical needs.

Mercedes hates his guts because he installs stuff in the cars that mercedes themselves say can't be done.
But the dealers love him cause he saves their butts every time they get electrical problem cars they can't figure out for weeks and he usually pin points most problems within thirty minutes.

his # is 404-277-9383. Jim LaPlant.

tell him John sent you.