Would this be one of the MB Service Wagons?
 

1983 300td with a list of odd wiring add ons .One is an inverter outlet to 110 in the rear cabin area less the inverter . Second is a wiring setup for a computer of some sort,also rear cabin. Maybe for parts ordering or billing.I just found a buyer who wants the car and have discovered other oddities while cleaning and fixing things.

Is it white? Dumb but AFAIK they were all white with blue interior.

I would think they'd have those items, but don't know for sure.
The pic is from their 1985 Turbo Diesel brochure.

Pics?

I saw one of these cars at a Casino in North County San Diego. I should have taken a picture.

Although it is quite possibly an ex-service wagon, those items were not part of the equipment.

Parts were either in the wagon, or not. Usual things in the wagon were fuel, filters, oil, coolant, tools, jumper-cables.

I blew a hose on an '87 TD service wagon, was fortunate that I had a knife with me to cut the hose shorter and re-install, IIRC there were two gallons of anti-freeze in the car.

The service wagons were IIRC just normal wagons, no special equipment except the graphics.

VIN ?