Chevy Trailblazer EXT 03, 55,000, serpentine belts seems to be squeaking adn the RPM Gauge just stopped working. I am not sure what could be the problem I would appreciate it if anyone can help. I was told to just lube up the serpentine belt when it squeaks. I'm not to confident on the answer that I was given so if some can advise or confirm this claim. I would be very greatful.