Have spent a frustrating few hours trying to figure out why the rear (cargo) cigarette lighter socket has no power on my W164 2009 ML320 CDI. Front and Centre ones both work fine. Fuses all fine (#44, #45, #46) Haven't checked the fusible links under the cargo area, but I am assuming they wouldn't be for the 12V socket anyway? Any ideas???

Would anyone have a wiring diagram for this model so I can trace the power through from the fuse box to the socket?

 

Are you referring to this socket? If so, remove key out of ignition. Pry out socket with plastic pry tool..

Turn ign. on and test BLK/Blue wire for 12v and test Brn. wire for GROUND.

 

I had this and the blade connector had come off the terminal on the rear of the socket.

 

It's an ISO 4165 socket

https://en.wikipedia.org/wiki/ISO_4165

Like all USA Mercedes, yours came with the "smoker" option. You can replace your actual cigarette lighters with more ISO 4165 sockets if you wish to make it officially a nonsmoking car.

 

The cargo area socket is not cig. lighter, it is a 12v charging port. Cig. lighter sockets are completely different from charging ports.

 

A good idea ikchris ..... many thanks

 

Thanks for all the responses folks. It's raining today, but as soon as its decent outside I will go and remove the connector and check behind it as suggested. Stay tuned ......