Mario D

Took my 2015 3500 Silverado into the dealership as my onstar system died and no gps, etc. They changed out the HMI module and reprogrammed the module. Now the radio screen is black, no onstar, no phone, etc. They couldn't call GM as it was late Saturday afternoon so now return Monday morning to see if they can figure out the problem. I removed the RDO fuse as was suggested in this thread and it did not solve the problem. BTW, the original diagnosis was the onstar module was bad so I purchased a used one online and the dealership attempted (at least that's what they said) to reprogram it and could not. An hour and a half with 7 onstar reps came to an end by them saying that used modules can NOT be reprogrammed for a different vehicle.