You have a major battery drain.
You will need an ammeter to test for the drain, do you have one?
If not a multi-meter with a voltmeter, ammeter and ohmmeter costs as little as $7 or so, get one and let me know when you are ready to test, but you would disconnect the negative battery terminal and place the ammeter inline with the negative test lead on the negative battery post and the positive test lead on the end of the negative battery cable, then turn the meter to ammeter or dc amps around the 50 mA scale if it's an analog meter or close to it if digital. Remove the key, shut the doors, truck and remove the hood light bulb if it has one, wait 30 minutes for everything to go to sleep, but you can glance at the ammeter anyhow. Then when the modules are asleep, the total drain should be less than 50 mA, or 0.050 amps, that is for the computer, radio presets, etc anything with memory and that is the most the ammeter should read. If it reads more than that, something is draining the battery. I assume it will be over 1 amp, but whatever it is first before pulling the fuses, make sure it's not a short in the alternator causing it so, remove the wires from the alternator, then read the ammeter again. If it is still over 50 mA continue on. If it drops some but till not under 50mA, it could be more than just one thing shorted. So, start removing the fuses, one at a time and look at the ammeter after removing each fuse to see if the ammeter drops. If you have to keep the door open in order to pull fuses, just push in on the door jamb when looking at the ammeter. Continue on until you find out when pulling what fuse or fuses allows the ammeter to drop below 50 mA, then hook the battery back up and find out if everything on that circuit works and if not, now use the voltmeter to trace where that item or branch circuit has voltage, then all of a sudden looses voltage, that will be the spot where the short is.
Let me know which fuse it is and I'll download the wiring diagram for that fuses circuit.