When I was setting up the new (to me) van, which has separate stop and
turn lights, I thought I had everything connected correctly.
The 4 way flasher test showed everything to work - the stop and turn
lights all worked.
Then I put my stick between the seat and the brake pedal, and went back
to check out. NO brake lights!
If I had relied on the 4 way flasher test, I would have gone out with no
brake lights.
Turned out that no converter was needed. Apparently the factory wiring
harness is set up to connect to combined stop-turn lights on most N.
American trailers since the early '50's. I disconnected the separate stop
light wire from the converter and everything worked right.
Al G.