Here's a specific question about the
principle involved in tricking the head unit into thinking it is in reverse. I hope it will clarify not only my understanding but also for other people who struggle to understand not only reverse signals but also parking brake and vehicle speed and similar.
My thinking is in layman terms (and promise you don't laugh, but rolling eyes is OK) :
there is a wire connected to a switch thing at the transmission and that wire goes on to the head unit. When reverse is selected, the switch switches and electrons flow in the wire to a pin of the head unit telling it that reverse is selected. Now, if reverse is not selected HOW THE HELL THEN can simply fiddling with the wire at the head unit eg another switch, beyond the transmission switch and therefore has no electrons flowing, trick the h/u?
Do not fear causing me embracement
with the answer, I am embraced enough by simply asking.