Interesting. Didn't occur to me about the blank speedometer being a safety issue and the idea of filing with NHTSA. I'm going to go the friendly route first and see what they find out at the dealership.
Please do not go the "friendly route" only. That's not being friendly and you are not squealing on anyone. The law mandates that GM is supposed to self-report such defects to the NHTSA but you're working with a dealer, not the vehicle manufacturer. I've seen full-blown recalls done where an investigation was started with as few as four (4) owner complaints that resulted in the recall of thousands of vehicles.
That particular one recalled almost 27,000 vehicles and Ford already knew about the problem, made fixes a year earlier, and blew it off as not being a safety problem but the NHTSA disagreed and a recall was mandated.
The vast majority of NHTSA recalls are self-reported and self-initiated, not mandated by the feds. The system usually works but owners have to do their part.
See:
https://www.nhtsa.gov/report-a-safety-problem#index
Keep it short, factual, and non-emotional as you did here and the report will work. The NHTSA manually reviews every single submission and forwards 100% on to the vehicle manufacturer (not a dealer) within a few business days.
That's how you get attention on your problem.
Ford, on one of their truck chassis models, had a recall a few years ago for the exact problem; the dash going black for a few minutes to forever. A recall was ordered. People were driving around using their GPS as their speedometer until the recall occurred.
