Check your grounds and check the positive connections. Something like this happened to me. And it ended up being a loose ground. Also could be voltage regulator but they rarely go out.

 

It wouldn't be a bad idea to charge the battery to see if it holds a charge, as well as the other things that have been mentioned already. As Nighthawk said, a good 12 volt battery that is fully charged, should read 13.8 volts.

If your fully charged battery doesn't go higher than that after starting, I would look into the cables, connections, fuses, and the alternator. I imagine you would hear the fan belt squeal if it was slipping that bad, but it wouldn't hurt to check that too.

Let us know how you make out, Chuck

 

The truck should run off the alternator regardless of battery condition. The way it died sounds like it was running off the battery. Again check your cables and grounds carefully and clean all connections. Jump the truck and measure the voltage from the alternator. As suggested, turn on all lights etc to simulate a load. You want to see close to 14 v. Anything under 12.5 may be bad news. Electrical problems cause chain reactions. A bad alt. can kill at battery and regulator and a bad batt can kill the alt. You want to see less than 5 amps draw with everthing off. Even that is a little high. Charge the battery and leave it disconnected over night and see if it holds a charge.

 

I recently had a similar issue, with my truck it was the previous owner had used a jumper wire to make the fuel pump relay run constantly which in turn drained my battery overnight similar to what yours is doing. It is at least worth checking out.

 

Amazing what goof ***** do to their trucks... cobble them together with coat hangars and duct tape...

 

Here is the deal. Ive had the battery tested, alternator tested and I have checked it for parasitic drain with no results. Relay one clicks in sync with the interior lights on and off. Charged the battery back up Ive taken the fuses out, radio out and still nothing. No light are being left on. That ground on the pass side kick panel is clean and not rusted. The truck wouldnt start when we had a cold snap and then today when it rained 60 degrees out. It sat for 24hrs both times PLEASE HELP ME !

 

Have you checked the starter for excessive draw? Also the cold usually means weak battery. The charge is lower in cold. Finally check the battery and starter connections. Test for voltage drop across the wires and ground leads.