Let's start at the problem I had first. My alarm would go off for no reason and then the gate adjar on the dash came on and would not turn off. Got to the point of draining the battery. Took it to the dealership and they said it was the insurement panel and I replaced that. $800.00... Uggghhh... Now the gate adjar light came on while driving and the interior dome lights would flash when the light came on. Any ideas??? I am mechanically inclined but (yes I'm a woman) don't know where to start and don't want to take it back to the dealer. Thanks for any sugesstions

 

I had this problem recently. Mine was due to washing the truck, then having a very cold night freeze the switch on the back hatch.
When I went to work in the morning, the hatch ajar light was on, as well as the doom lights.
I opened and closed the hatch a few times, and the lights all went off, eventually.

My guess is you have a problem in the rear glass hatch sensor/switch.
Look for a button/sensor that the glass contacts when closes, somewhere along the area where the glass and liftgate meet.