Voltage plays havoc with electronics. A few good recommendations are here. Also try cleaning your grounds under the hood and on the frame. Use electric grease when you reconnect them. If I'm under the hood or under the truck, and a ground is near me, I'll clean and reconnect it as a matter of routine. Good luck.

 

I second checking the connectors, however, be careful to pull them apart parallel to each other. It is also wise to do a drag test with a similar sized pin for the female connector to make sure the receptacles aren't spread out.

 

You mentioned the tailgate is removed and you have faults on the camera module. Did you put the plug in the camera harness when you removed the tailgate? You may want to check it anyway, I’ve had moisture get in capped plugs that took the network down and gave me abs and advancetrack warnings and faults. If it’s not capped, there is a special cap plug that comes with the new truck for that purpose.