My rear liftgate is not locking. While driving, chimes often and doors lock on 2008 Chevrolet Suburban 1500

The automatic rear liftgate has not worked for 6 months. We turned it off and have been opening manually although each time we open or close, we can hear the mechanism trying to work. Went to close yesterday and won't lock. Car chimes every 1-3 minutes while driving and automatic door locks lock 2 or 3 times in a row. Back right electronic door lock hasn't worked for about 6 months as well.

Asked by for the 2008 Chevrolet Suburban 1500