Every so often (and possibly related to work being done), the brake lights on my 57 3100 just stop working. Sometimes, they start working again on their own. This has happened ever since I started working on the truck. Maybe I shift a ground or something while working and it fixes it for a while. I don't know. But I do know that every time I get into the truck to go somewhere where it matters that they work, they don't (as in the Devil's Backbone Brewery Tour this last weekend). Brake lights worked fine the day before, then the morning of...nothing.
Turn signals work. Recently installed a new aftermarket turn signal switch because my old SignalStat 900 shorted out and fried half the wiring under my dash (learned a lesson about fuzed power that day, so not a total loss). The brake lights worked fine after the install of the turn signal switch for about two weeks.
I have power at:
The line that goes from fuze block to the turn signal switch
The brake light wires themselves (turn signals work)
Tail lights
I have the tail light housings grounded to a clean, solid ground on a nearby frame crossmember.
When I fully depress the brake pedal and activate the switch, I get no brake lights. I have done this with running lights on and off, turn signal on and off.
I need to check for power at the brake light switch yet. Will do that tomorrow probably.
So, does the brake light 'system' get a ground from the housing being screwed to the bottom of the floor pan? My driver's side floor pan is a swiss cheese pile of rust-eaten former metal, so that may be part of the problem. But a switch being a switch, does it not just break the power wire?
Suppose I could direct ground with a temporary wire to the housing of the switch if that's where it grounds and test the lights that way. But with the tail lights already grounded, is this a silly exercise?
Any help is appreciated.
Jim
