Cooling water over temp light and buzzer

[DoraPearl09]

I am fairly new to a C & C 36 with a Yanmar in it. Does anyone have any ideas why my cooling water over temp light would remain on and the buzzer stay on after I have started my engine when it is stone cold? From what I can tell and have found I'm pretty sure the temperature switch is not even hooked up. It doesn’t make sense to me. Any ideas?

Thanks,

BC

[Omatako]

It is unlikely that the temp sensor not being hooked up will cause the problem you describe. Ordinarily the sensors take the circuit to ground when the temp gets up there and thus the light/buzzer are activated. If the sensor is disconnected it cannot make the circuit to ground.

However . . . if the wire that is disconnected from the sensor is accidentally permanently shorted to ground (terminal stuck in a small space) then of course the circuit is made and the light/buzzer are activated.

Alternately, the wire is still connected and the sensor is simply faulty.

[DoraPearl09]

Thanks for the reply, I will check it out.

[Northeaster]

Not to ask a dumb question, but.. I don't know which panel you have. Are you sure that it is the water temp light, and not the charging (alternator) light that is coming on, along with the buzzer. Normally the charging light and buzzer will come on for a couple of seconds, until you rev up the engine enough to start the alternator charging. If you leave it idling, it would normally continue to light / buzz until it is revved up.

[Omatako]

Mine doesn't do that. If I start with neutral throttle (idle speed) all the lights and buzzers go out almost immediately.

I guess different sensors have different sensitivity

[Shortman]

in the alternator light check switch on the panel. If you have the "large" panel, you should have this switch. Same happened to me after a knockdown washed over the panel. The switch was old & corroded and the water did it in.