Lights flickering while parked without keys and being on also locks are locking and unlocking while driving

What would cause that?

Like the windshield, struts and springs?

Usually stays on until I turn engine off, Could this be a sensor or something more serious?

Replaced gas cap with new GM cap. And still have the same problem.

It looks like you would use a cross-tip screwdriver to remove the access panel in the trunk, but it isn't coming loose for me.

The car will bing three times dome lights will come on and trunk ajar light will flash.

The AC runs but it blows warm air. I was told the climate control system may be at fault? Or the door actuator is failing. Is there an inexpensive way to confirm the problem, before commiting to large repair bill? Any estimate on how much this repair would run?

What happens if I don't fix it right away?

car has about 118000 miles on it. This is my friend's car but I have driven it several times and am about to buy it. Hope this is not an expensive problem.

body control module is good but cluster is not reading correct

I changed the thermostat. The fans are not turning on and the fluid does not appear to be circulating. Any advice on where to start? Could it be sensor-related?

I understand the inlet connection requires 2 wrenches.
What about removing the front outlet connection?