1999 5.7l EFI Mercruiser High Temp Alarm

I have a 1999 Mercruiser 5.7l EFI Bravo 3. Just started the boat first time in over a year. Started okay but am getting an alarm. I put a code reader on it and read code 15 - over temp. Clear the code and start the engine and it comes back. The alarm sounded before the boat warmed up. Looked everywhere for a temp switch with tan/blue lead but cannot find it. The 2 wire temp sensor and the 1 wire sensor (tan wire) for the instrument panel are at the thermostat. But I have looked everywhere for the additional over temp switch with a tan/blue wire but cannot find it. Am I missing something? Can someone describe where it is supposed to be? Or does the computer just use the 2 wire temp sensor and set the alarm? Thanks Ted