Well, I was in the process of re-wiring under the dash, and was adding voltage reducers, winshield washer button switch, heater motor reducer and switch, and replacing the 6 volt cigarette lighter with a 12 volt "power plug" for accessories like my cell phone charger. I was a wise man, you see. I had disconnected the battery while doing this so I was well protected from shocks. But I was a little lazy, since I didn't want to down on the floorboards one last time to double check everything. So while in my cab, with the doors and windows closed, and the truck in the garage with doors closed, I made my battery connections.
Within seconds the positive cable was stuck to the positive battery post and the cab was full of smoke. I opened the door and jumped out and the smoke rolled out into the garage. My lovely wife opened the door from the house to the garage and yelled "I smell something hot!" (God love her!)
Luckily, I had only fried the wire to the new power outlet....and singed my pride! I bet you've guessed by now that 1) I didn't have an in-line fuse for the power outlet and 2) that I had connected the power lead directly to the power outlet ground instead of the hot post.....OOPS!!!!
I was amazed how fast a 12 guage wire could melt! No other damage. Put a fuse in, new wire and I'm back in business.
I think I'll change my name to "old Double-Checker"