eTrailer has a plug-in wiring kit that plugs into the same connectors as the OEM ones, but costs less than half what Chrysler wants for theirs. Mine should get here today or tommorrow.
The reason I bought it was that I hard wired a cheapo 4-pin and found that while it all works, the trailer's brake lights flash when the right turn signal does. I would just let it go except that I just acquired a "compact travel trailer", a 1972 Aristocrat Lo_Liner that should be perfect for towing behind my CRD. It has elect. brakes, so I need more than 4 wires. I'm getting one of those fancy new sockets that has both 4 and 7-pin connectors (also from eTrailer) and it connects via the 4-pin for the normal stuff, with extra wires for brakes and aux. power.
The Lo-Liner is lighter, shorter and narrower than standard travel trailers. It sleeps 6 (if everybody is friendly) and has compact stove and fridge, but has no shower. Mine has a closet for a porta-pot, which is fine for what I want. Some of them have toilets but without a holding tank, so you have to be hooked up to a drain to use it.
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TxAshurst
'05 Liberty CRD
Mod.s to date: Added biodiesel and mud, but not in the same places; Upgraded tires to General AT2 M+S 235-70R16; U-Haul towing receiver; front tow hooks