Help with Alarm

[tin]

OK I have a question I need help with...This is the audible alarm from the boat I think its bad everything looks fine with the wiring ....If this is hooked as soon as I connect the battery it goes crazy...so I pulled it off the boat checked across all the wires no shorts...Now I put my meter on the Alarm itself and it shows an open does this mean its bad ? I know stupid question but I'm really stumped on this one.....Any help Please

 

[tin]

Re: Help with Alarm

Its a 1989 Sylvan mercruiser 3.0 I/O ...I'm assuming temp and oil pressure alarm....As soon as the battery is hooked up it goes off no heat in the engine ,,its actually winterized....So I removed the Alarm put a meter on it and its full open across the two hookups....One lead the 12 volt is always hot with the battery cable hooked up the other runs to the temp gauge but is hooked to what looks like a ground or the bracket suppport for the guage...any ideas.....

 

[burp]

Re: Help with Alarm

Tin,

If the battery is hooked up and the ignition switch is in the off position, I wouldn't expect to hear any alarm. Now if the ignition key is in the start/run position without the engine running, I wouldn't be surprised to hear an alarm as you would have no engine oil pressure. What I'm uncertain of is if and what is monitored on a 1989 Merc 3.0L engine. Low engine oil pressure, high engine cooling temp and low outdrive lube reservoir level are monitored on newer and larger Merc engines.

 

[tin]

Re: Help with Alarm

Burp,
Yeah it sounds with the key out of the ignition just the battery hooked up strange......I'm almost sure its monitoring all three based on the gauges and the wiring but not really sure... I have already ordered a new alarm only 18 bucks I'm really hoping its an open in the horn that is causing it ...They had a bunch of wires mixed up they had the ignition wired to start before the ACC postion ughhhh.....

 

[TerryMSU]

Re: Help with Alarm

Burp,
Yeah it sounds with the key out of the ignition just the battery hooked up strange......I'm almost sure its monitoring all three based on the gauges and the wiring but not really sure... I have already ordered a new alarm only 18 bucks I'm really hoping its an open in the horn that is causing it ...They had a bunch of wires mixed up they had the ignition wired to start before the ACC postion ughhhh.....

Not likely the horn. Some types of horns will be an open circuit when checked for continuity. In any case, I have a hard time conceiving of a bad horn causing the horn to sound. I can see a bad horn not sounding, but not a bad horn sounding. I do not know much about the rest of the system, so I cannot give you any other advice. Sorry about that.

TerryMSU

 

[tin]

Re: Help with Alarm

OK everyone here is the current status....Replaced the alarm,,, No good as Terry pointed out above :facepalm:.....So the boat is wired like the following....... Light Tan to the temp sender this is a ground ( or at least its open to ground at the sensor ) Light blue wire to oil pressure this is also showing an open to ground at the sensor ( this reading is at the senders themselves and not the dash ) wires run into a black box ( resin sealed so I can not open it ) then off to the dash... all gauges appear to move when I turn the key to ACC position.. The alarm is wired to hot on one side and I'm not sure but where would the other end be hooked up to ? It was originally hooked to the metal that holds the gauge in place but this is a ground so the alarm would go off !!!...correct ? ...So should the wire be hooked to the light or light blue at the dash...Then when the temp or oil sensor closes because of an over heat low oil condition it would close to ground ??? This one is driving me crazy..........But spring is coming HELPPPPPPPPP

 

[rickryder]

Re: Help with Alarm

I know my alarm sounds when it's grounded.... I would think its sensing no oil pressure. It should go off when the engine fires up. Not sure of the wiring in your boat. Have you tried to google a wiring diagram for your boat?

 

[tin]

Re: Help with Alarm

The problem is the Alarm goes off when hooking up the battery .......No I have not been able to find one yet...

 

[rickryder]

Re: Help with Alarm

Mine grounds to the sensor for temp on my OB.... I have the diagram for my Four Winns I'll look at it I would think they would be similar.


I have 3 wires on my alarm tan blk and purple.... It really dosen't show the sensors

 

[tin]

Re: Help with Alarm

Also I turned the ignition to ACC disconected the wires then grounded them both Oil and Temp went to full so the gauges are good and looks like the wire is good...Must be where the negative side of the alarm hooks up to...... anyone ??

 

[rickryder]

Re: Help with Alarm

I would think you have 2 temp sensors....1 for the gauge and one that goes to the alarm when the sensor hits overheat.

 

[tin]

Re: Help with Alarm

found some Wiring diagram's http://www.boatfix.com/merc/Servmanl/16/16F4R2.PDF

 

[rickryder]

Re: Help with Alarm

Seems like the tan/blue wire is the trigger wire to your alarm. See if you can find the tan/blue wire under your dash.....I would say it connects to the ground wire that is on the alarm.