To start its a 1988 XJ, 4.0 Aw4.
So today went to leave for work it seemed like a bead battery. I went under the hood and the negative cable was loss. Tightened it down and it fired right up. After work while visiting a friend I went to leave and same crap. No start, no nothing, headlights didn't work northern did the horn. No starter click nothing. I can stay here for the night but got to fix it first thing in the morning.
So I'm wondering where to start? I got a solid 12.65 volts on my multimeter from the battery and when I was driving it I was ready 14 on the gauge. Any help would be appreciated.
Cheers

 

Wiggle the terminals. If it was loose it could of gotten corroded causing it to not be connected.

 

Tried that and still nothing.

 

Check your grounds. renixs have infamously. Bad grounds

 

Put your meter on the battery terminals and then try to start the engine while watching the meter, the voltage should not drop below 10.5volts.

 

Between a bad ground on the oil dip stick and lose terminals that were worn out I got it fixed this morning. Bombing down gravel roads seems to rattle a lot of stuff lose when the shucks are going out.