1993 Pro-V 150 Temp Warning Light

My overheat warning light in the digital gauge blinks as soon as I turn the key, the outboard does not even have to be running. I have tested the thermoswitches (both) and they check out fine. I have even tried fooling the circuit by inserting resisters where the thermoswitches should be to see if I can get the light to go off or get the audible alarm with no luck. Any ideas as to what is causing the light to blink? By the way, the engine runs fine even with the light blinking, no drop or restrictions in RPM's. Please help!

[boats.net]

Make sure dip switch in back of tach are set for 2 stroke engine, all three switches should be in down position for that motor.

Thank you for this suggestion. However, I'm a bit confused. The overheat warning light is part of a multifunction digital gauge- the gauge has speed, trip, and time, but no tach. My tach is on a separate gauge. Also, what do the dip switches look like? I have looked at the gauge and have not seen what I think you are describing. All I have seen is a dial with an arrow pointing to mph or kph. Thank you!

[boats.net]

Ok you have the older style gauges, I didn't pay any attention to the year of motor. There is a gray wire with bullet connector next to gauge harness on engine in engine pan. Make sure it is connected.

I have confirmed that all wires are connected and in good condition. Could it be a problem with the gauge itself? When I bought the boat the gauge worked fine, but now the mode button no longer works, meaning I cannot switch between speed, trip, and time. Perhaps some water/moisture got into the gauge and corroded some of the circuitry? Is there any way to test the gauge to confirm this? Again, thank you for your help.

[boats.net]

should have 12 volts between yellow and black and between red and black going to gauge, if do gauge is probably bad.