Rear Seat 12V Outlet Project


Due to an upcoming long-distance driving trip, I decided I needed a 12V power port for the rear seat.  I am planning letting my granddaughter use my IBM ThinkPad in the back seat to watch DVD movies on our drive.  I was going to buy the 12V power cord for the ThinkPad, but I found it to be less expensive and more versatile to buy a 300W inverter.


The M-Class (mine is a 2001 ML320) has three 12V outlets.  One in the front seat ashtray located in the center console, another in the  front passenger side foot well area, and the third on is in the rear cargo area below the “D” pillar.  The inverter has a short cord so locating it in the front seat area was not an option.  Due to the fact that it needs some ventilation, locating it underneath cargo in the rear would not be an option either.  I decided the best course of action was to install a port in the rear seat passenger area.


My first trip was to Radio Shack where I purchased a 12V power socket.  It can either be mounted into a thin panel using by drilling a 1.25” hole in the panel and snapping it into place, or by using an under dash style bracket for bolt-on style mounting.  After examining the passenger area, I finally decided the best place would be in the rear of the center console, near the ashtray and cup holder.


I wanted a place that could easily be repaired in case I made a mistake.  This could also be important since I am leasing the vehicle and I don’t want to discover at lease end that they want the socket removed requiring a $500 replacement part.  Anyway, after some careful examination, I found that a good spot would be on the cup holder door.  I removed the door and proceeded to drill the require one and one quarter inch in it.  I mounted the socket and put the cup holder back together.


Everything looked pretty neat, but the socket, even with its plastic cover, just did not look right.  The Radio Shack part was just not up to Mercedes Benz standards.  I began to think I had made a mistake and was about to call the local dealer to order a replacement cup holder door, when I got an idea.


I noticed the 12V outlet in the cargo area.  It has a nice spring-loaded cover that looks very much at home with the rest of the vehicle.  I began to think that instead of buying a new cup holder door, I should buy another one of these outlets.  I removed the outlet from the cargo area and made a few more cuts, and installed it in the cup holder.  It looked great, so I completed the wiring by tying it into the cigarette lighter circuit in the center console.  I have order a replacement socket for the cargo area that should be in stock within a few days, costing around $20.  All in all, everything has worked out quite well.




(Click on the thumbnails for larger pictures)




Here’s the finished project:





Here’s the shape of the cutout required for the Mercedes Benz socket:




This is what is looks like behind the scenes: