Yanmar Control Panel

[thaeni]

I have a Yanmar 3gm30f. When I turn the key on the alarm does not sound, also when I
shut the engine down it does not sound. When I energize the test switch the alarm works.
Any ideas on what I should be looking for.
Thanks

 

[Ken Cross]

The test switch simulates an overheat and lights the overheat light. You should also have an oil pressure light and an alternator light. All but the overheat should be on with the switch on but the engine not running. Each one of these should set off the alarm. Attached is a wiring schematic. This should be easy to figure out with a multimeter. If you don't have one they are dirt cheap at Harbor Freight.
Ken

 

[Benny17441]

Like Ken indicates the toggle switch only tests the "temperature" sensor circuit but not the "charging" circuit nor the "oil pressure circuit". The fact that you hear the alarm when you activate the toggle switch is a good sign as it means that the "buzzer" which services all three circuits is operational. That buzzer is rather expensive at close to $200 if it ever needs replacing. Check all the electrical connections (clean and tight) at the back of the panel and at the engine end. If everything looks well but no power to the sensors I would conduct a visual inspection of the wire harness from engine to panel. This means crawling under the cockpit sole. Look specially around bends for chaffed harness insulation; as the hull flexes over many years it can cut through the harness at sharp fiberglass edges. Get a digital multi meter and check for continuity and voltage in the circuits.

 

[Charles Erwin]

Do any warning lamps turn on at key on?

Charles

 

[woodster]

they should untill you get the engine started

 

[whatfiero]

It's the oil pressure switch bad mounted to block by filter take electrical connection loose it a 9 mm nut and touch connector to ground block with key on you will here buzzer now replace switch charging cir may not alarm if batterys fully charged

 

[Ken Cross]

In the event that you just can't stomach the high cost of a new buzzer, it can be replaced with an electronic alert (like a Sonalert) some diodes and one dropping resistor.
It just depends on how much engineering you want to do.
Ken

 

[thaeni]

No. No lights

 

[Charles Erwin]

Ken - 99 cents

 

[Charles Erwin]

No. No lights

The problem is as above noted - but here is a bit more detail.

Since no lamp and no buzzer - your oil pressure sender/wire is the culprit. Either the oil pressure sender is not working or the wire has come loose from the sender. The sender is located at the lower right on the front of the motor.

Verify sender works by measuring (ohms) from the sender contact terminal to the motor block. If resistance is infinite replace the sender.

Verify the wire is attached to the sender. If so take it loose, turn on the key, and touch the wire to the motor block. This will cause the lamp and buzzer to activate. If this does not work the wire is loose between the sender and the lamp in the Yanmar panel. Remove panel locate (corroded) problem and repair.

Yanmar also uses a connector - that connects all the feeds from the motor to the panel. This connector may be compromised. Take it apart, and clean the contacts. This connector is at the motor rear proximate to the backside of the starter motor.

Charles