Warning Buzzer Not Working

[rognvald]

My instrument warning buzzer/lights stopped working. There are no engine issues. Is there a simple test that can be performed without pulling the panel? I have difficult access, if any, to the back side of the panel which is in my starboard lazarette. It is a type B panel for a Yanmar 3gm30f. Thanks, Rognvald

[a64pilot]

Usually the light and buzzer are both triggered by switches, overheat and oil pressure.
They are usually normally closed switches, a multimeter should be able to tell you if one is open circuit, and a simple wire jumper ought to be able to fault isolate a switch.
You do have two lights, but one buzzer, right?
Are neither lights coming on with the ignition? If so then I doubt it’s the switches, that sounds like the panel.

Can’t you simply remove the screws and pull the panel out to gain access?

[Jim Cate]

I'm tempted to start a thread called "most sailors can't do simple electrical troubleshooting"...

but I won't because highlighting other sailors shortcomings isn't really nice.

As to your problem, since both lights and sonic alarm have simultaneously failed, one likely issue is the 12 v supply to those items. Not sure about Yanmars, but commonly the switches provide a ground return, completing the circuit and activating the alarm.

Jim

[Wotname]

Originally Posted by rognvald

My instrument warning buzzer/lights stopped working. There are no engine issues. Is there a simple test that can be performed without pulling the panel? I have difficult access, if any, to the back side of the panel which is in my starboard lazarette. It is a type B panel for a Yanmar 3gm30f. Thanks, Rognvald

For something simple to try, scan down to the emphasised bit.

Which lights have failed?
Does the engine still start - presumably yes as you state there are no engine issues but????

I am presuming your oil light has failed as that and the charge light are the only ones that illuminate at start up but without knowing exactly, it makes trouble shooting from afar difficult.

The +ve feed to the lights and buzzer is supplied though the same fuse and switch as the engine start solenoid so if the engine is starting OK, then the +ve feed is OK at least as far as the start switch (key or push button).

Some Yanmar B panels have a buzzer "off" switch and some don't. Check yours and make sure if any switch is fitted, that it is in the normal (not silent) position.

But the first thing I would do is find the oil pressure switch which is near the oil filter and short out the terminal to the engine block. With the key switch 'ON", the oil light should illuminate and the buzzer sound. If so, remove the short and and the light and buzzer should remain "ON". If not, your oil switch is faulty.

If the light and buzzer stay "ON", then remove the wire from the terminal and the light and buzzer should now be "OFF".


Next, find the over temperature alarm switch (somewhere near the head and/or thermostat). Again short it out to ground, The over temp. light should illuminate and buzzer should sound.

If you are not getting any lights or buzzer with the above, you will need to get access to the back of the panel. As a64 states, remove 6 screws and the panel should come forward.

[Wotname]

Originally Posted by Jim Cate

..........
As to your problem, since both lights and sonic alarm have simultaneously failed, one likely issue is the 12 v supply to those items. Not sure about Yanmars, but commonly the switches provide a ground return, completing the circuit and activating the alarm.

Jim

Yep Jim, that's correct. The Yanmar B panel has an external fuse in the loom near the alternator that supplies 12 V+ve to the key switch and the start switch. The same 12 V+ve also supplies the lamps and the +ve side of the buzzer via the key switch. The various idiot light switches supply the ground return to the lights and the buzzer. The buzzer has 3 -ve inputs all internally isolated. I think there might have been some really old buzzers that only had one -ve input and the various alarms were externally diode isolated but I haven't seen one. Some of the B panels have a "Alarm Off" switch which removes the +ve feed to the buzzer. Of course, the idiot lights remain in circuit.

[akprb]

Originally Posted by Jim Cate

I'm tempted to start a thread called "most sailors can't do simple electrical troubleshooting"...

but I won't because highlighting other sailors shortcomings isn't really nice.

As to your problem, since both lights and sonic alarm have simultaneously failed, one likely issue is the 12 v supply to those items. Not sure about Yanmars, but commonly the switches provide a ground return, completing the circuit and activating the alarm.

Jim

It isn’t nice but is necessary and compassionate ;-)

A basic knowledge of electrical trouble shooting and how to use a basic multimeter should be in every serious cruisers holster.

Period, dot.

[Teknishn]

I second Wotname's post. Additionally, check that the 2 plugs on the engine wiring harness and the 2 plugs behind the panel are clean, not broken or corroded. Have had them become unseated in the past while doing other work in the engine compartment and then found no/limited functionality at the panel.

[Cadence]

Originally Posted by Jim Cate

I'm tempted to start a thread called "most sailors can't do simple electrical troubleshooting"...

but I won't because highlighting other sailors shortcomings isn't really nice.

As to your problem, since both lights and sonic alarm have simultaneously failed, one likely issue is the 12 v supply to those items. Not sure about Yanmars, but commonly the switches provide a ground return, completing the circuit and activating the alarm.

Jim

Jim, I love your opening paragraph. Most sailors should but it seems many new to sailing/boating aren't.

[rognvald]

Thanks to all for the positive input. My Yanmar engine service manual doesn't detail these elements so I'll get to work with my multimeter and check these excellent suggestions. My panel does have an on/off switch for the buzzer but that is not the problem. I am hesitant to pull the panel without doing some simple checks since we are underway and there are no engine issues--I just serviced oil/transmission and fuel filters yesterday. Thanks again for the ideas. Best . . . Rognvald

[Burghy]

Originally Posted by Jim Cate

I'm tempted to start a thread called "most sailors can't do simple electrical troubleshooting"...

but I won't because highlighting other sailors shortcomings isn't really nice.

As to your problem, since both lights and sonic alarm have simultaneously failed, one likely issue is the 12 v supply to those items. Not sure about Yanmars, but commonly the switches provide a ground return, completing the circuit and activating the alarm.

Jim

So there must be a fuse somewhere... do you have a idea where is it thanks

[Burghy]

I have the same problem no light no buzzer when i put ignition "on" rpm works engine is starting... but no nothing from the lights and buzzer ��*����