I am trying to figure out the wiring to my cigar lighter. The Sat Nav/ Phone chargers do not seem to work in it. There is only a single red feed to the unit but there is a second connector (not attached) with a black and a mauve wire. Should this be connected to the lighter as well as there are a couple of unused spades on the lighter? The wiring diagram I downloaded from Gomog seems to show 3 wires at the lighter but does not identify colours.

Anybody know what it should look like?
Andy