I spend several days deciphering an indecipherable wiring diagram and tracing wires, cleaning connections, and grounds to figure out why the alternator light on the ‘68 Saab wouldn’t come on.
Only to find out the problem was the bulb was dead. It doesn’t look burnt out, the filament isn’t broken, and the glass is clear - but it will not pass a current. Of course I didn’t think to actually check it beyond looking at it when I started. New bulbs are on the way.
PS: if you ever go to hell, all wiring diagrams look like this.