Engine alarm volvo penta MD2020 not working

[fontmell]

Hi
Help please all the warning lights are working but not the audible alarm. All the wres are connected. Does anyone have any experince of same fault?
I suspect the alarm unit has failed. IF I am correct in my assumption can i test it ? If so how? It looks easy to remove
Thanks in advance for you responses

 

[gregcope]

When the horn should sound you should see a voltage across its contacts.

Or remove the horn and test it with 12V.

Otherwise its the Alarm module or wiring from it.

 

[VicS]

Hi
Help please all the warning lights are working but not the audible alarm. All the wres are connected. Does anyone have any experince of same fault?
I suspect the alarm unit has failed. IF I am correct in my assumption can i test it ? If so how? It looks easy to remove
Thanks in advance for you responses

If you feel you can test the alarm itself that sounds like a plan. Perhaps do as Gregcope suggests and check the volts across it when the test button is pressed.

It is controlled by an electronic circuit, See the attached diagram. (Later models might be slightly different. ) There are numerous possibilities for an electronics failure as well as failure of the alarm sounder itself.

Note that the alarm normally operates from 10volts, which is dropped further by the diodes in the circuit. You might test it using a 9volt battery if you have one before trying 12 volts if it does not work on 9 volts . ( Observe the correct polarity )