Grimlens in the electronics

All fuses are tested good.
Small annoyances but would like to get them fixed. Anyone able to offer so suggestions on what to look at/test?

1: The temp and heading on the mirror sometimes work and sometimes nothing.
2: If i try turning on high beams they only stay on when im holding the switch. As soon as i let it go it goes back to low beam. Both lights are good.
It seems like the instrument cluster lights should be backlit during the day?. During the day the instrument cluster is very hard to see. At night everything seems to be working as it should. If i manually turn on park lights during the day, the dash backlights come on.
3: The lift gate will not open with the remote when the overhead console switch is in the remote position. The park lights do flash. If i push the close button the lights flash but nothing happens. If i put the switch in manual the gate opens with the switch on the lift gate. I did replace the actuator on the lift gate but i think the round gear thing on the lift mechanism needs to be replaced?
4: The door chime for keys in ignition or headlights left on has very low volume.

I do have some codes
U0186 Lost comm with audio amplifier. Radio seems to work fine.
U0199: Lost comm with door control module "A" Doors function fine. Windows and switches.
U0200: Lost comm with door control module "B" Doors function fine. Windows and switches.
B2615: Passenger compartment dimming 2 circuit.
I did clear the codes and will check tomorrow after work to see what if any return. I suspect they popped up when i bought it, The battery was so low it would not even click when trying to start it.

How old is the battery?

07 Yuke Denali right? Definitely remove battery, slow charge overnight & have parts place load test it.

If you haven’t replaced -/+ battery cables yet, do it now. They can be the source of rot on the inside & pristine on the outside. Once replaced you can be assured any codes coming up are not the cables creating them from resistive current.

Yeah the battery is about 3yo.
I usually upgrade most battery and ground connections. Just have not got to it yet.

Electrical gremlins=grounds problems, battery problems and/or alternator problems and cables problems. Especially when they all show at once.

I checked again for codes a few days ago and none were set after driving it a week or so.
I still think it was because the battery was almost dead.
I still need to check clean grounds and run new charge/battery/ground wires with better gauge wire.
Cold and cr4py out, makes it had to get motivated when i don't have a dry warm place to work