2004 Mercury 2 stroke, Model 50ELPTO, on a 2004 Triton Pro Crappie model. RPM gauge quit. Worked intermittingly for a time but now has quit. Does it sound like I need to replace the gauge or look at other things also? I'm assuming there is a wire coming from the motor. I can't find it on Seloc manual wiring diagram. What color is the wire & does it go thru the key switch?