i just had this problem. Check the light board that is inside the OBC. Its a pain in the ass to get to but thats probly the problem.
Edit. If this board is blown it will only effect the Tachometer, engine temp, defrost, hazard lights, and OBC backlighting. Not spedometer and fuel gague
<span style='font-family:Geneva'><span style='font-size:14pt;line-height:100%'><span style='color:red'>Fox</span></span> <span style='color:gray'>the Pirate</span>
Diplomacy is saying "nice doggy" until you find a rock.</span>
I live my life one quarter mile at a time, and for those 23 or more seconds I'm free.