mine don't work at all, cant be bothered to fix it as its not required for the MOT
The only good thing about reverse lights is people know you are reversing, I may get a loud beepy unit in it.
And the horn thing that sounds like a clowns horn! lolor one of those speaker things on the back of council lorries that shout WARNING, THIS VEHICLE IS REVERSING lol.
The thing with a manual switch is I'd leave it on, lol. I might just replace the switch. Any idea of the cost? what does the job involve?