I had a problem with my fuel gauge going all the way up when I turned the headlight switch on. It was recommended that I add a better ground to the instrument cluster. Today I removed the instrument cluster and verified all the screws on the back were tight. I then made a ground wire that a ran from one of the instrument cluster frame screws to the dash frame. It was clean and shiny, bare metal. It's affecting the temp and fuel gauge. I had them recored last year by instrument specialties as well as a new converted instrument voltage regulator. I called and the recommended checking the orientation of the cluster round plug to make sure the wires were in the correct order. I compared it to my 65 fsm wiring diagram and everything matches. It's frustrating because the whole dash harness and engine/light harness are all new replacements. I can't remember when they all worked right. It's a pretty simple harness, not much plugged in. It's only affecting the temp and fuel gauge when either the key is turned to power or engine is running. The fuel goes all the way full and the temp goes all the way high. Is there a way I can verify the problem? Could it be a defect in the ignition switch? The ignition switch is fairly new. It has an extra terminal on it that says ground. Where does the ignition switch get its ground? I took the switch out of the cluster and let it hang but had the chrome collar on it and everything worked the same. Does it get it's ground from the chrome collar?