thanks Greg and to the others who answered. Still questions:

Did you tap into the single lines (brakes, taillight, signal)? Are
you using relays, directly from battery? I looked into some
commercial solutions and in the moment I am confused as I don't know
how all these different plugs physically look (just looking at
pictures is unfortunately is not a big help to me). And I found round
ones (6 connections, 7 connections, flat 4...)

        Karl.

At 3:12 PM -0400 04/06/2005, Greg Potts wrote:

>Hi Karl,
>
>When I built the westrailer I used a bus tail-light housing but
>wired it to a standard 4-wire trailer harness. (Red lights only)
>That harness was connected to the bus' wiring with a $20 U-haul
>5-to-4 wire conversion harness. Unfortunately the quality of those
>harnesses is pretty questionable... they were failing annually on
>me. So last spring I added turn signal lights to the westrailer and
>an additional 2 wires to the harness, and that works fine. The bonus
>to that system is that when someone with a standard harness uses the
>trailer the "normal" lighting circuits still work as usual.
>
>www.pottsfamily.ca/westfakia/Westrailer
>
>Happy trails,
>
>Greg Potts
>Toronto, Ontario, Canada
>
>1973/74/79 Westfakia Conversion **Bob the Tomato**  LY3H
>1977 Sunroof Automatic L63H/L90D
>1988 Vanagon GL 8-passenger Automatic
>http://www.pottsfamily.ca/westfakia
>http://www.busesofthecorn.com
>
>
>On 6-Apr-05, at 8:07 AM, Karl Ploessl wrote:
>
>>how do people with trailers hook up the lights to the trailer? Are
>>the connections (plug-outlet) standardized?
>>I am thinking to get a small trailer (already got the hitch)...
>>--
>>Karl
>>'81 Westy "Jenny"
>>Wilmington, DE