When door is opened inside light starts blinking and power loss alarm and door ajar stays on after the door has been shut

The interior switch has 3 positions. First position is " light stays on" center position is"off". Third position is "auto on and off"

Replace the door ajar switch.

Try spraying wd40 into each door latch. Do it one at a time then open and close the door about a dozen times spray some more in there after about 6 open and closes. Do this with each door and even the hatch. This should clear ya right up.

it sounds like you have a door open that is why the light is on. it may not be a actual open door but a faulty door ajar switch. that would explain why the alarm keeps going off. i would start by opening and shutting all doors includingthe hood and hatch.
if that does not fix it-a gm dealer with a tech 2 scanner should be able to located which door ajar switch is bad.

Check your door latches. Since the light stays on, one of them isn't reading properly. Once you get that fixed, the remote should work. The light problem could be related. The computer thinks the door isn't shut so that part of the system thinks you aren't moving.

you may have a broke wire in the door harness

I had this problem. I had to have a sensor in the door replaced.

there is a switch in each door that senses the door is open, it is called the door ajar/courtesy light switch (imagine that), they stick and have this problem, replace it.

What happens when you remove both switches, and wires? What happens when you use a jumper wire acros both wires, on both doors?

not sure what to say but check recall on your vehicle might be a wide problem...could get fixed for free