Ford 3000, 1966, 3 cyl, gas: The tractor is clean with no rust and runs great. Of the 5 indicators in the Instrument Cluster, ONLY the generator light works. The oil light, temperature gauge, fuel gauge and tachometer do not work. I want to get these indicators performing again. Any idea if there is a common denominator causing the 4 indicators to not work while the generator light works normally? How would I diagnose this problem?