Marine Trader engine start buzzer

[seattleboatguy]

When I turn on the key for my port engine, I hear a buzzer, as you would expect. But, no buzzer on the starboard engine, except on very rare occasions. Both engines start up just fine I hit the start button.

On the picture below, I think "4" and "3" are for the port engine, and "1" and "2" are for the buzzer-challenged starboard engine.

I know that "2" and "3" are Cole Hersee 4099 buzzers, easily purchased from amazon or elsewhere.

My question is, what on earth are "1" and "4"? I think "1" might be dead. I can find no part number on "1" or "4". And, I don't understand why they have 3 posts instead of 2. There is 13.5 volts between "A" and "B", and between "C" and "B".

Any ideas concerning what these 3 post mystery boxes are all about, and where I might find a replacement?

1987 Marine Trader 38 with twin 135 hp American Diesels (very similar to the more common Ford Lehmans).


Thanks.

 

[Martin J]

could be you have 4 buzzers ie seperate oil,water temp, low water etc. Buzzers not normally the problem, normally sender units.

 

[Comodave]

Usually a low oil press sensor per engine and a high engine temp per engine. Since you hav dual engines, you can swap them to see if the problem is the buzzer or is the problem the wiring or the sender on the engine.

 

[warfdog]

Just guessing based on the appearance (Cole Hersee case) and three connections one being ground...newer version here:
Cole Hersee 40212 Dual Rate Electronic Alarm 12V DC

Should be easy to confirm by connecting power to connectors. Alternate guess some kind of relay to convert +V to a grounded terminal on closure, for matching engine buzzers config (i.e. for high-bilge alarms, etc.).

 

[seattleboatguy]

Usually a low oil press sensor per engine and a high engine temp per engine. Since you hav dual engines, you can swap them to see if the problem is the buzzer or is the problem the wiring or the sender on the engine.

I think you and Martin had the right idea; one for pressure, and one for temperature. I swapped the buzzers left-for-right and right-for-left as you suggested. The original problem remains. So, I guess the buzzers are okay, and the problem is either a sender unit or a loose/broken wire.


Thanks very much.

 

[Comodave]

Simple way to check the wire is to just run a long wire from the sender to the buzzer without running it inside the walls. Just unhook the lead at the buzzer and the sender and temporarily hook up the wire over the deck and see if it works then. If not you can swap the senders between the engines but not between the oil pressure and high temp on one engine.

 

[High Wire]

Bottom 2 are buzzers. Top 2 look like relays.
Do you have a wiring diagram?

 

[seattleboatguy]

Bottom 2 are buzzers. Top 2 look like relays.
Do you have a wiring diagram?

I do not have a wiring diagram.

 

[Martin J]

Hi Seattleboat guy
Just take a jumper wire and ground out the sensor.