2003 ignition harness questions

[Weedy]

Good morning and thank you in advance for any and all help. I’ve got an 03’ Merc 60hp 2-stroke that I am replacing the ign harness. When I start the motor the over heat alarm goes off and won’t stop. Obviously the motor hasn’t over heated. Also the is plenty of oil in the tank. On the key switch side of the harness, the tan w/blue stripe doesn’t go anywhere and it’s not touching anything. Is this suppose to go somewhere or does it just dead end at the harness not connected? I did disconnect the overheat sensor, along with the low oil sender and it still stays on. WHY??? lol Again, thank you for any and all help with this matter. Hope y’all have a wonderful weekend.

 

[Texasmark]

On some harnesses, that wire and an other are dressed on the outside. If like on the larger engines, find the OH sender...on larger engines its on the rear water jacket cover that the spark plugs protrude through. There will be a screw with a small device attached to the screw having a wire attached. Follow this to the wiring harness connection in the engine and there would be a Tee where the blue/white stripe (as I recall) wires from the oil tank level sensor are also attached. This Y then connects to the tan/blue stripe wire that goes to the control box and under the dash for a visual alarm if used on that boat.

The wire has 12v on one side the Piezo alarm device, and then the ground for that device is the wire going to the engine proper. The OT alarm shorts out at about 20* F or so above the stat opening temp....which I forget the temperature where it opens. When it shorts out it puts ground on the tan wire which closes the circuit for the alarm module and it sounds.

The wire you mentioned and find at the control area, or under the dash is for the visual light bulb indication and normally is mounted in the dash with 12v on the other side of it. Not a problem for that pigtail to be flopping in the breeze.

All from memory with my 90 and 115 engines....could be some minor errors.