Have a good 12v input to gray IGN wire on gauge and good ground on black lead. 4 conductor modular plug seems good and tight on signal wires to harness. Have never seen REV, OIL, TEMP, CHECK ENG lights prior to or after starting engine. Motor "beeps" prior to starting and it runs fine. I've tried a new gauge to no avail. I'm not sure what to look for on engine side of harness but I'm assuming I should at least see the OIL light on when key is switched on prior to starting