2017 GMC 4500 Savana Van
Air bag light on setting code B0091 front air bag sensor short/open. First off tested for proper ground & signal to sensor have a good ground( low reference) but no power to sensor. Now here were it gets fun, need to get to air bag module for further testing it’s located in the middle of the van under the mat, needed to remove seats and floor mat and other trim once there we had open circuit. Now testing from several different connectors were able narrow down problem from air bag module to connector X318 and from there find the corroded wire. Now some techs would just run new wire why i didn’t, this is a twisted pair for interference. Sectioned in new wire all back together and no more air bag light.