Constant alarm

[baddog11]

1992 MARINER 150 HP
SER# 0D124111
Turn key on has constant steady beep, believe it is overheat alarm.
Does it even when motor is cold, never goes away.
Oil injection was removed 10 years ago, this just started happening.
Is it the alarm module that is bad?
All wiring has been checked, grounds clean.
Any help is appreciated.

[half fast]

Is the buzzer in the control box or under the dash ? If in the c box something could have rubbed a wire and caused it . Find the tan wire on the motor and make sure it 's not touching a ground . hf ...

[drm]

Check your water temp sensors in the cylinder heads , if stuck closed it will lie to the alarm system and tell it the motor is hot. unhook wire i at a time to find out which sensor is bad. an over heat condition will close the switch to activate the alarm.

[tux974]

Hot horn is in the starboard head tan/blue wire.
:iagree: Sounds like it is grounding out.

[baddog11]

Thanks for the replies. Yes, the tan/blue wire is the one for the horn after tracing it out, and I can disconnect it and the alarm will stop.
My question now is with the wire disconnected is it safe to run? If I run hot will the alarm still activate with the wire disconnected? The alarm horn is in the control box.
Thanks for the help.

[flabum1017]

That wire is the sensor wire, with it disconnected, you will not get a horn when it over heats. You need a new sensor

[baddog11]

Thought so.
Thanks

[tlwjkw]

Thanks for the replies. Yes, the tan/blue wire is the one for the horn after tracing it out, and I can disconnect it and the alarm will stop.

Thanks for the help.

where did ya disconnect it?

[baddog11]

Where it connects to a common terminal mounted on the block.

[tlwjkw]

right place ta prove sensor!