Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
I am sorry your having this problem
they will all lock an unlock at random ?
does the interior light stay on like a door is open or it flicker on and off ?
will it randomly do this ?
will bumps make it happen or it can do this at a stand still ?
did this problem start out of the blue one day ?
was anything done to this truck to have this issue ?
from the sounds of this problem it can be caused by a door lock switch acting up signalling lock when you are not pushing lock or the lock signal wire from the BCM to the lock relay the grey/black shorting to ground to a bad BCM itself causing this issue
the best bet to narrow this down is to unplug both front door switch assembly electrical connections and see if it acts up which if it is going to act up just the rear door locks would lock if it still acts up
if it does NOT act up plug in one of the front door switches back electrically and see if it acts up if it does the odds are that switch assembly is bad if it doesn't act up plug in the other switch and if it acts up it is the switch you plugged back in electrically
if it still does this with the front switch assembly's unplugged then the grey/black wire from the BCM needs to be checked for any shorts from the BCM to the lock relay and repaired or replaced if bad
if that wire tests good the only thing left to cause this issue is a bad BCM i am sorry to say
you have to remove the door panel to access the electrical connections at the switches