Sleeper back wall lights

Are you talking 4” lights? If so the easiest way is a hole saw and then a rubber grommet. Just make sure there aren’t any brackets behind the panel where you want to cut.

 

You SHOULD have a rivnut setter in your toolbox, but go pneumatic or hydraulic if you plan on anything other than aluminum. Theyre handy.

For cutting small sheet metal cutouts (thin gauge), the tool you want is called a "nibbler", or as suggested above, hole saw for round

 

This sounds like a "Ask me how I know to check."

 

My grandfather said "some can learn from a book, some can learn by being told or shown, but some people just have to pee on the electric fence themselves"

I strive for the first, do okay at the second and much to my shame have extensive experience with the last

 

As long as they aren't blue.

 

Not me, but I’ve seen it happen. If it doesn’t come from the factory I usually leave it alone mostly because taking bunk interior apart doesn’t interest me. But if you pay attention to where the rivet lines are at and look at other trucks with the same bunk you can ballpark where the safe spots are at.

 

Had a mechanic one time while prepping a new truck put a self taper right threw a wiring harness in the floor of the truck while installing the fire extinguisher.

The truck had to be towed out of the shop bay to the local Volvo dealer. Turns out the ishift can’t shift with a bolt drilled threw it’s wiring lol