I don't know about the service bulletin or where you can find it but if everything worked correctly before the replacement of the wiring harness then I would say the dealer who changed it is responsible for the problem. If the dealer does not want to correct the problem then go over their heads to the district manager for GM, the process is usually posted in the back of your owners manual if you are not satisfied with the dealer or the outcome of a repair. Because this is a recall I do not believe that your warranty would have anything to do with having it repaired without charge.