Battery Draining

[razorboy]

Hey Guys,

So I have a draining battery while the truck is parked.

Did a little research here on the site and wanted to check a couple of things with you.

Brand new battery, same size as original. Runs down after a couple of days of sitting to the point it needs to be jump started which I never do. I remove the battery and recharge before attempting to start the truck.

Battery fully charged was displaying 12.70 volts.
After turning off truck, battery displayed 12.49 volts.
Once truck had gone to sleep, displayed 12.55 volts.

This was after I remove the rear upper hatch release assembly and here is why.
The two times the battery drained and I recharged and installed, I got an immediate rear hatch open warning which of course it was not.

The rubber area covering the hand release has dried out, rotted and fallen off so when I get a car wash, water has definitely gotten in there. Hatch wouldn't work at all until the area dried out. Took the assembly off and did see corrosion on the pins of the connector, on the license plate light terminals and some on the PCB where the connector terminals join the PCB. I figured this is a decent culprit to chase first so thats off the truck now and I have 12.55V with the vehicle asleep and doors unlocked.

Before I attack this with an amp meter to start chasing down circuits, is this a normal voltage sag for a sleeping truck?

Thanks in advance