2000 frontier

[Kv0071971]

My son went mudding in his truck then right after all dash lights came on, now it won't start and dash lights don't work but headlights work. I got him a new battery since it was old. We had alternator checked and it's fine. We can jump it to get it to start but then it will die in 10 mins and not start. Any ideas I am at a loss. Could it be a relay?

[centralcoaster33]

Seems like water got somewhere it shouldn't. Or a loose connection was created from being jarred around maybe. I'd check all the stuff on and between the battery and starter. Even remove and reconnect wires and grounds. Then I'd check related fuses and relays under the hood. Seems like the alternator isn't connected properly to me, but I don't know. It should have a fat power wire screwed in, a smaller ground wire screwed to the chassis of the alternator, and a set of wires in a plug for some balancing control electronic stuff.

[Desert Rat]

do the tail lights work? Those are on the same fuse as dash lights....so that could just be a fuse that shorted.
A multi meter will tell you if the alt is charging and it'll also tell you where your battery is. Look for crud around batt connections that could be inhibiting conductivity. The battery should be somewhere around 12.6 volts with the truck off and somewhere around 14.2 or so when running.