I have an older vehicle that I intend to use as the tow vehicle for a planned 13' Scamp which is fitted with electric brakes. The PO tells me it has an inertial braking system; I don't quite understand what that is but understand it to be stock to the trailer. It's fitted with a standard US style 7-pin trailer hookup. This is a 2023 or -24 Scamp but IDK for sure if it has incandescent or LED stop/tail/turn lighting, I'm guessing the latter.

My rig is a European 1991 VW Vanagon Syncro imported to the US and has amber turn signals stock. So I am pretty sure it is a 3-wire system (vs. a 2-wire or multiplex type). It is fitted with a European style N-Type 7 pin trailer / towing socket, which if necessary, I would replace with an appropriate North American style socket. This means there currently is no signal wire for an electric brakes separate from the brake signal wire. Nor any separate aux power wire. Just the following:

1) Turn Signal Left 2) Turn Signal Right 3) Brakes 4) Reverse Light 5) Side Tail Light Right 6) Side Tail Light Left 7) Ground

Frankly I can't tell what I need: a powered 3-to-2 wire converter, an electric brake controller, or a non-powered converter.

I also don't quite understand why (most if not) all the converters (Curt, Hopkins) have 4-way flat wire (vw. 5-, 6- or 7-way) connectors.

Any help is appreciated.