I have a 90 K1500 5.7L 5 spd that while the key is in the on position, ( engine on or off), all the gauges will "flutter" a little if an powered accessory with a switch (turn signal, hazards, pwr windows, pwr locks, headlights etc.) Some more than others. The oil pressure gage moves the most and the fuel gauge moves the least. The spedometer does not move at all. The temp and volt gages slightly "flutter". I believe this to be cab/chassis ground problem. But do not know where the proper ground would be. I checked the ground next to the battery, the instrument ground on the fire wall, and the three that I know of on the engine. Anyone else had this problem and possibly found a solution??