2010 ML350 Bluetec

Have taken out my cigarette slide out tray and lighter to put in a switch panel for my Volunteer Firefighter strobe lights , a spare switch and USB ports with a Voltage meter on them.
I'm using relays so load on the switches won't be an issue.

Question on the wiring colours to be sure
When measuring them with a multi meter I am getting the following;

Orange - Ground?
Black Grey - 13.9 volts ( with it running )
Brown White - 5.14 with lights on and .5 with lights off


Thanks in Advance

 

The wire colors are not the same as yours, but the BLUE wire is the 12v supply and the BROWN is GROUND. Do not use the last wire as it is too thin,

 

Had to take off the passenger toe kick and under dash cover to get add the firewall grommet to run my wires under the hood , and had to pull the cigarette lighter plug from there and it was only Orange and Black/Grey. Traced it back to the ground that is in the toe kick and Orange is the ground. Black/Grey is the 12V supply , the small Brown/White is the for the light ring around the cigarette lighter by the ash tray thus the low voltage.


Wired it to that and everything is perfect .

Mis judged the depth of the ashtray slide tray was mounted so I need to shim my switch panel out a bunch , but like the way it turned out.