NO the aux socket is the ciggy lighter that sits in the centre console. I believe ulysseman is looking for a permanant +ve for the bypass unit wiring for the towbar electrics. I could be wrong though.....
I think it's for the optional interior light
Where do you pick up a 20a supply I have found a spare fuse in engine compartment marke f36 which is for trailer but I have not a clue where this wire terminates. Ie it goes from fuse box somewhere regards Ken