I'm sure that there are a number of possibilities, but one that happened to both my 01 Ram and my wife's 99 Durango required the replacement of the whole gauge set. We had Lojack installed in both trucks upon new delivery from the dealer. I guess part of that installation required the opening and removal of the gauge area of the dash to run some wiring, etc. Since the gauge set is really just one big computer chip, the best anyone can figure out is that the Lojack installer zapped it by mistake with static electricity and shorted out the circuits. Since none of this could be proven for sure, it was just chalked up to faulty parts and replaced under warranty. Both cases happened about 3 years apart and seem too weird to just be coincidence. All was fine since then. Maybe in your buddy's case there is a loose wire somewhere. I would hate for him to need to replace the whole thing, as it was a $700 part for our vehicles, plus labor. Good thing we didn't have to pay.