The weirdest thing happened today. I got done replacing my fuel filter. I started it up, and it cranked a while until it got fuel and then it started up just fine. I reparked it, shut it off, and then I decided I should probably check for leaks. I turned the key while the door was still open and it made a clunk as it started to engage the starter and then everything went black: no dome light, no warning lights, absolutely nothing. I took the key out and then tried it again and there was not a sound or even the faintest light. I went back out after about an hour and the dome light came on and the warning lights came on, but when I went to crank the engine it did the same clunking sound and then everything went completely black again. I checked the voltage at the battery and it read 12.7. It seems like since there was voltage, at least the dome light or the warning lights would show dimly or something, but there was nothing. Not even a click when turning the key. Any thoughts on this? Is there some sort of master relay or something that I can check. I haven't had a chance to get the battery tested, but it seems like it might be something more!

 

your battery terminals/connectors are corroded or loose. Make all the contacts shiny with a wire brush. Replace stripped side-post retainer bolts if needed. I'd bet your battery is fine.

 

^ X2 ^ loose battery connections cause weird problems on these trucks. but it wouldnt hurt to go down to your local parts store and have them test the battery and alternator for free.

 

Agreed, try cleaning/tightening your battery cables first.