A Buick Lacrosse drive his car to our garage for repair dashboard light states two rear doors open.And I write this real repair case here to share,hope this mini post will give your some ideal for your work.
The dashboard light states rear door open and the window regulator unstuck sometime
Trouble Diagnosis and Solution:
Technicians detected the communication between BCM(Body Control Module) to other modules,found some communication problem from BCM to rear door control modules.
Check the related circuit diagram,the bus nodes J234 from BCM to door control module locate behind the rear seat.And J234 node have been corroded badly.
Technicians restored the J234 node,then the trouble symptom disappeared.