CONTINUOUSWAVE

Turn the key
No alarm horn
Oil light and fuel light but not overheat light come.
Switch bulbs but same info.
Where do I go next?

I had a 1994 150 HP XR2 Merc in which the alarm horn stopped working as well. If I recall correctly the overheat sensor had froze (being a saltwater motor) & it actually was a very big deal because I later overheated the motor without alarm. That overheat warped the block & ultimately retired the motor. I'd check that first unless I'm not relating the problems correctly.

What have you found out? The overheat sensor could be acting.