Let's just say, when someone tells you to check ALL your bulbs, check ALL of them. History: I am the owner of my late grandfather's 51 Ford Club Coupe. My dad and I rewired it using a Ron Francis wiring kit (super easy to do, just time consuming because we ain't 20 years old anymore) and had ZERO problems. EVERYTHING worked PERFECTLY. One day, I'm driving to the folks house and whammo - no left turn signal or brake lights. I leave the car at my folks because it's dark and I pick it up the next day to drive home. Problem was a blown 15amp fuse. Replace fuse and think I'm good. NOT the solution I wanted. Soon as I stepped on brake pedal, POOF! Blown fuse. Replace fuse and start checking bulbs. Both EXTERNAL turn signal bulbs on the front are good. Both EXTERNAL bulbs are good in the tail. Brake filaments in perfect condition, both signal filaments good. Time to start checking grounds, so over, under and through EVERY ground. They're good. DAMN. Time to start tracing wires and checking for bare dead shorts. Nothing. Maybe it's the physical turn signal switch. Take apart, check, reassemble, it's fine. Get a new one. Same problem. Hydraulic switch on master cylinder? It's fine too... What's left, what's left? What about the interior dash indicator bulbs? Hmmm... Pull them out - they look good, no visible blown filaments or blackening. Go to the parts store with bulbs in hand - find the match - 6V!!! Dangit! We're on 12V now. Didn't realize they were still 6V, don't know how we missed switching them out. Buy 14.4V bulbs. Install and now everything works. Let this be a lesson to you all, when someone asks if you've checked every bulb, make sure you checked EVERY bulb. dv
Because that's when you solve it In my defense, it's the dang bulbs. When they are only stamped with a weird number and not a power rating, you just don't know. Until you know... The bulbs were stamped 55, which means nothing to me, and the replacements were 1480 or something like that.
So at what point did the little light bulb come on in your head? Glad you fixed it, and then told us what you learned. Good lesson for all of us!
Last week I was just going over every step of our process and the things we did, and I thought: "What could it hurt to check those bulbs?" I remember long ago the bulbs used to be stamped 6v or 12v on the bases, but apparently "they" stopped that practice. All three that I removed looked good, the left one must have developed an internal short somewhere, the filament was unbroken and unburnt.
You probably had wire on one of the bulbs rubbing and shorted to ground. You changed the bulbs and by default moved the wires. Yes it is fixed for now but you may want to give the wiring a second look. A 6 volt bulb will burn twice as bright as a 12v one with 12V to it It will burn out fast but wont pull 15 amps of current.
Believe me when I say I'm keeping an eye on everything, I'll be checking every time before I drive somewhere.