External siren on NSS12

[Owen]

A while back I hooked up an external alarm on my Garmin 556 for use as a drift alarm if teh boat is anchored off the beach.

Tried to do the same on my mate's NSS12 last week and can't get it working.
According to the manual, the blue wire is the external alarm.
It (the blue wire) was wired directly to a piezzo buzzer.
I hooked up a switch so either the buzzer or the siren could be chosen.
The siren is wired through a relay.

We selected "activate siren" (not sure of wording now) in the options of the unit, but no matter what alarm we try, the unit only sounds the little beeper in the head unit.
I confirmed that both the piezzo buzzer and the siren work if fed 12 volts directly to the point where the blue wire is connected as installed.

Anyone got a clue why it won't work?
Seems like there is no output on the blue wire. Can't remember if I put the volt meter on it while an alarm was going off (a weeks worth of beer on North West Island since then), but pretty sure I would have checked.

Just wondering if there is some other configuration in the unit that needs to be set??

[Boat Hog]

You could try posting on Invisible Communications Marine Electronis Forum, they have a section there for Simrad NSS.
http:/www.invisiblecommunications.com.au

Cheers