Phil wrote: "Only adjustment is depth by shim or in my case, I had to machine away some the face or shoulder behind the threads"

I think I need to do just that. Using a lathe to remove some 0.030-0.040 of the shoulder would push that pin deeper and touch the switch contacts. That switch is realy not old, may be 80 to 100k miles.

Only problem I dont have lathe, but I will look for someone that does little jobs as a hobby. I will operate these backup lights manually until I find somebody with the proper machine tool.

Thanks a lot for your reply.