Thanks, Jake.

I could bypass the wires that lead from the internal (car) signal wiring by usint a battery as you said. I'd test the 5/4 adapter box by disconnecting it from the car, then touching the wires as you said. So for turn signal with tail (head) lights, I'd touch those 2 wires.

If something doesn't work right, it's the box. If everything works fine, it's the car wiring. Let's hope for the box to be faulty. Not sure what I'd do if the car wiring were the problem.

Cheers,
Danno