Can anyone help with a wiring diagram for a tow hitch, or can some one confirm if my car would have come equipped with the wiring already. (1989 525I) There are several plugs under the trunk liner, one of which has about 6 male pins with a female clip attachment that has no wires leading from it.

Also I have had mixed opinions whether or not I need a surge protector to guard the computer. Any thoughts ?? Has anyone just tapped off the existing wires??

Thanks heaps
Garry