wiring camper shell dome light to battery

Hey everyone. i’m having some trouble with wiring my dome light provided with my camper shell to my battery. in theory I thought I had it correct, it works, but kills my battery and requires a jump start overnight. even when the light is almost always off. This here is the dome light, both the dome light and the 3rd brake light are wired into a fuse box.The chassis at the bottom pointed at by the blue arrow feeds 3 wires, black, solid red, and white and red. all labeled in the photo. black is my ground, red & white is my brake light, and solid red is my dome light. I have the dome light fed underneath the taillight compartment and wired to the frame underneath my truck directly to my battery. As I said, it works as it should, but kills my battery overnight, and sometimes will die as soon as I park it not allowing me to even lock it with my key fob. toyota gave me a new battery recently due to the factory battery giving me a ton of issues, it was replaced a month ago and has not given me any issues until connecting the dome light to it, so I doubt the battery is the issue. I know there is still a current traveling even when my truck is off, but is it enough to kill my battery? what is my issue here? is it possibly my ground? it is barely hanging onto a bolt in the tail light compartment but that idea was given to me in a youtube video. The dome light is something I would love to keep as an option because I go camping a lot and it is super convenient. electrical is clearly not my strong suit even on a simple job like this, so any help or advice is greatly appreciated!

 

also, not sure if it’s important but the instructions to install the dome light recommend a 12 VDC feed, but I accidentally bought 14, my friend said that should not be an issue, but i’ve considered that as well.

 

My Cargo Light was originally wired into the Parking Light wire at the tail Lights. You could probably do the same? But, the light only works when the parking lights are ON when wired this way.

You could check out my thread on connecting the wire to the OE Cargo Light switch (which I haven't really finished yet).
Brake Light Mod? | Tacoma World

 

Nothing wrong with 14 awg wire for a 12 volt DC circuit.

 

the truck must be on if I end up doing that, correct? might have to go that route if I can’t figure out why it keeps killing my battery. thank you for the help I appreciate it a lot

 

I believe you are correct. But I'm not 100% sure. I never tried to turn on my cargo light with the truck off. I just wanted mine to work like it was OE.

 

Did you ever figure out what the issue is.
I'm currently trying to figure out the best way to wire up the chassis input on that leer box. Can't really find much on it.