Weird electrical problem, help!

Coming back from lunch today, I tried to start my Samurai and the starter just clicked instead of turning over. No problem, it does that sometimes, it's caused by a design flaw in the Samurai's electrical system. When it happened 3 times in a row that was quite unusual. Then the next time I tried to crank, all the dash lights just faded out and back in, there was no noise. I'd seen this happen before with dirty battery terminals but I was pretty sure mine were quite clean. Tried again, same thing. Tried once more, the lights dimmed out and never came back on

There's a sight glass on the battery and it should look green if the battery is in good condition...it's green. Terminals are still shiny and coated in generous gobs of vaseline to keep crud out, but with no idea what to try I removed and re-attached them. Then it fired right up like I expected in the first place

Any idea what could cause this? Failed individual battery cell perhaps?

Edit: Just remembered that when I put the terminals back on I also tightened a "sub-terminal" on the positive terminal that goes to the starter so that's something I can check. It wasn't rattling around but the connector attached to it was movable.

Even if the battery terminals look clean, there could have been enough dirt or corrosion on the inside of the terminal so it wasn't making a good electrical connection with the battery post.

Although you can't rule out a bad battery cell yet, I would double check the battery cable ends. Especially where the cables connect to the end terminals. Since messing with the cables seemed to solve the problem, they probably have something to do with the problem. More than once I've found a cable that looked good fail under a load. Its usually caused by a bad crimp or solder connection where the cable meets the terminal, or sometimes there is even a rotten spot in the middle of the cable.

GameboyRMH wrote: Edit: Just remembered that when I put the terminals back on I also tightened a "sub-terminal" on the positive terminal that goes to the starter so that's something I can check. It wasn't rattling around but the connector attached to it was movable.

And you solved your problem. It was just loose enough that it wasn't making a good connection. The increased current draw because of that was causing the light dimming problems.

My old Toyota pick-up used to do that. The starter would get "stuck". Sometimes a quick hammer shot to the starter would free it. I got really good at learning to park it in such a way to ease push-starting... Maybe that's why I always back my cars into parking spaces...