Inconsistent function from brake light switch

[swartzdesk]

My brake light switch has been giving me troubles. Turns out the guy who owned the truck before me had a metal washer between the switch itself and the little clip that holds it all in place. I was told that screwed up the switch that was on the truck when I got it -- after seemingly working fine for years.

So, I replaced the entire thing and tossed the metal washer.

Went fine for a while until I was at the bank one day, and couldn't get the truck into gear until I "cheated" the system and started the engine with in in neutral. I fiddled with the new switch and checked the connections (it's hard as hell to get to, btw), and couldn't replicate the problem again and the brake lights started working, so I move on.

Fast forward a few months, and it happened again. I installed a little mirror on the back of my tailgate so I could monitor at least the middle brake light while driving. Sure enough, it would work sometimes ... but mostly not -- like 80/20..

I replaced the brake switch again. Figured, what the heck -- $10 part.

Now, the brake lights work almost all the time (since now I'm checking quickly each time I press them). HOWEVER, the lights seem to not come on like 1% of the time. Overall, I suppose that's a decent success rate -- but not one you'd want for your brake lights, right? Very odd. Seems to happen when I'm cruising at about 45, then I flick my turn signal and then press the brakes -- like three of the four times the brake lights haven't come on, it's been after I'd activated my turn signal. And the other time was immediately following a misfire where I had used my turn signal.

Does the functionality (or lack thereof) even make any sense?

Any other times I've have intermittent working brake light switch, it's been closer to like 50/50.

Lastly, I think back to the metal washer that used to be there. Obviously, the previous owner obviously put it there for a reason, right?

Do you guys think a washer (not metal -- perhaps plastic or rubber/nylon) might do the trick?

Or is the problem likely old wiring that needs to be looked at?