Thanks Phat.. That makes it a little easier. :)

Nothing wrong with checking all that out.

If the alarm isn't going through self-test at startup though, there can be no doubt about it being bad. Unless I'm mistaken it doesn't even address the sensor inputs until AFTER the POST - power on self test.

Now that makes sense. I never thought about the alarm's POST and it's significance. If, when I turn the key, it just automatically starts sounding without going thru it's POST first then it makes sense that, just like a computer's motherboard, something's wrong with the unit before you even get to the other sensors.

Just had a similar issue with a brand new system check gauge on my 19' skiff. instant overheat alarm after going through the start up sequence on a cold engine. Replaced the gauge under warranty.