Alternator/generator/regulator problems of the 2009 Chevrolet Suburban

Vehicle continues to have random electrical problems after adding new grounds, new alternator, new battery, checking contacts. It's been at 4 repair shops including a chevy dealer and continues to have problems. Doors cycle on lock/unlock, lights cycle dimming, abs and other indicator lights come on, lose acceleration and vehicle stalls and dies. Seems to happen more frequently in cold weather and after a �rest� may or may not start no rhyme or reason. Has baffled mechanics for over 2 years. Pls help.