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I have seen W123 with trailer hitch... so you shouldn't have problem either. Easy way to hook up the wires is at the taillight wiring harness where you put bulbs.

Caution - I _do_ run a hitch on my 81 300D - but see the following article:

They caution agains running ANY extra load on the brake light circuit - even to the extent of running the standard American

1157 brake light bulbs. Apparently, too much current through the bake (ok, brake) light circuit can be damaging to your cruise control - and tapping in extra trailer lights definitely qualifies as extra current.

I run a special unit that detects power on the brake-light circuits, but pulls the power for the trailer brake lights from a different source (I pulled extra wiring from my cigarette lighter circuit, as I seldom light cigarettes while slamming on the brakes). Contact any reputable trailer/hitch dealer (NOT u-haul) about this module. As I recall, it was about $45-$50 USD - cheaper than frying your cruise-control. So far, no problems.

Cheers,

Conrad

Ahh... I c... sounds like a simple relay setup and use power source from elsewhere.

Yeah, sort of - it's a solid-state thingy that's supposed to be very low drain on the control circuit. Much lower drain than a conventional wire relay. Probably the kind of circuit that MB SHOULD have used in the cruise control to start with to avoide dumping the full amperage of the brake lights through it. Oh well, they can't get it right every time.

Conrad