I have been running with one of the cheap
wireless receivers and remotes for 2 years on my boat
. Worked perfectly. (Like this https://www.ebay.co.uk/itm/2x-12V-Wi...-127635-2958-0
Positive on the box wired to 12v+
The 2 control wires wired to the windlass
And the black -ve taped off to nothing
For some reason this worked (with the -ve taped off)
I stupidly thought this was ok till I tried to wire in a new box (like for like) which didn't work
till I wired in the 12v-ve to the -ve on the receiver.
Is it possible the original was faulty? Now I think about it, I am unsure how the original was working at all. Any clues?