I brought my 2019 Sierra in for service at 8000km and to check why the Service 4wd light kept coming on. Dealership ran diagnostics and said the 4wd module needed to be replaced. The truck has been in the shop since December 16th, I keep being told that the part is still being manufactured. I am beyond frustrated with GM at this point. I expect some serious reimbursement from GM to rectify this wait