Hi. I own a 2004 Chevy Silverado, 4.8 L V8, 70,800 miles, good condition. I am having intermittent problems with the guage cluster. Sometimes the speedometer does not work at all, sometimes it works okay, sometimes it registers too slow or too fast. Same thing with the oil pressure guage. All the other guages seem to work okay. Has anyone experienced this before? Any ideas what could cause this? I've tried disconnecting the battery in the hope that something would re-boot or re-set to solve my problem. No luck. Does anyone know where I can find a wiring diagram for my vehicle. I'm hoping a wiring diagram will give me some clue of where to look.