I bought an L-2500 Tribute that had sat in a store room for a few years, one of the switches was not working correctly (can't remember which). I ran a drop of switch cleaner down the switch toggle and exercised the switch for a couple of minutes and haven't had any more bother with it.
My guess is that the silver contacts in the switch had oxidised with not being used.
Doing a little work with some contact cleaner is where I'll start Fred. I saw that mentioned in a previous post and if it was you who suggested that thank you. If that's not the issue I'll need to take a peek at a diagram of the stock wiring scheme to compare mine to it before I can attack that.