yes. Yes you can.

 

You're going to need a wiring diagram and a few test tools will be handy. First, check that your battery is not actually the problem. Both Autozone and Advance Auto will test a battery. There is a type of failure where the battery will charge but not hold it and it discharges all by itself but its not common.
Put an amp gauge between the positive terminal of the battery and the wire that attaches to the battery to see what kind of current draw the fault is drawing. A 12V light bulb can be used and the current draw will be proportional to the brightness of the light. Troubleshooting involves disconnecting sections of the electrical system while monitoring the current flow out of the battery. Since the battery is going dead while the truck is not running, be sure that you have the keys out of the ignition and the doors closed. Having the interior light lit will mess up the troubleshooting. On my truck, the drivers door needs to be open to access the fuse box. One thing I might try is to pull one fuse at a time, close the door to the truck, and see if I still have current draw at the battery. If there is current flow, I'd open the door again, put back the fuse, pull another fuse, and close the door again and recheck for current flow. The point to remember here is not to be misled by the interior light or circuitry associated with the door sensors which might include the computer -- you need to have the doors closed.
The problem does not necessarily need to be associated with the interior fuse panel. There are other circuits that don't go through the interior fuse panel. Just have a mindset to monitor the current flow from the battery, and one by one disconnect the things that are connected until the current flow stops.

 

Yes, no doubt, it can be diagnosed. Agree with the above post. About ten years ago the shop i used found the glovebox light switch went bad causing a current draw. About the same time I went on ahead and disconnected the hood light cause i did not need it and did not want it causing any issues like the glovebox switch. If you can't find the issue take it to a pro.

 

You can use a piece of wood or something to hold the door switch down, so you don't need to constantly open and close the door while trouble shooting from interior fuse panel.
You may have bad alternator that's sucking all the juice from the battery. I had a Jeep, no two Jeeps that had bad diode in the alternator. It's easy to diagnose, just remove the cable between the alt and the battery and see what happens.