[outnumbered]

in link 2 that jim has put up is quiet easy to do i have done this on my v70 2004 straight from the battery, i have the 13 pin dedicated loom, the reason that i had to go down this route because whoever fitted the tow bar prior to my getting the car they had cut that wire at the dem end god knows why.as for tapping in to the reverse light i can see no reason why it would put any extra load on the cars loom if you think that it would you could always put in an inline fuse.
mike