Help. No time to search extensively, have to decide a.s.a.p. (did a quick search, but found too little info) Someone's selling a 5172 Thule bike-hitch and another person is selling a bike-hitch-to-trailer-hitch conversion (just the round knob to fit on the bike-hitch). (They are very rarely for sale and I cannot use one without the other, so that's where the rush comes from: I either buy them both, or none, and one's waiting for an answer and the other I cannot reach). Together they are about 150€/200$, but they are both used (slightly rusty) AND there's no electronics or connectors. New is 300€, but I cannot find if this is for both or just the bike-hitch-part (5172). Do or don't? And the electronics: do I need gizmo's because just tapping into the wiring will cause errormessages about blown bulbs? (E.g. Volvo's seem to need this or the measuring-circuitry will think something's wrong if your blinker suddenly draws double the current). Can I find a schematic on which wires to tap into for the hitch-connector? Thanks!!!