Key less entry not working rear liftgatenot open

[Falcon997]

Hi every body,

I have a 2002 Trailblazer for no reason key less stop working, rear door is not open, rear wiper stop working too and electric shut off when i turn off switch direct. I replace battery without benefit .
Before when i close rear lift gate i heard a sound for the lock now there is no sound.
I hope to find a solution to this problem here .

My best regards,
Tariq