silent alert horn

[Diverted Income]

I have a '95 75hp and a 169 series control box. Recently the alarm in the box stopped sounding when the ignition is turned on. Not sure if the alarm failed or the signal from the ECM. Anyone have any ideas? connections are good. Have not check for voltage at the alarm when ignition is turned on yet. That will be my first step. Should it be 12v or something less like 5v ? Just wondering if anyone has encountered this before?
Thanks!

 

[Laddies]

Re: silent alert horn

Goto the engine and short the water temperature sensor out if the horn blows the oil module is bad

 

[Barnacle_Bill]

Re: silent alert horn

I've got the same motor and recently had to replace the alarm module and horn. To test the horn turn the key on and check for 12VDC on one side of the horn. If 12V is there ground the other side and the horn should blow. If the horn blows replace the alarm module.

 

[Diverted Income]

Re: silent alert horn

So pull the wire off the temp trancducer and short it to ground? Oil module? Are you referring oil tank level or something on the pump?
Thanks

 

[j_martin]

Re: silent alert horn

If you look at the cap on the tank on the engine, there are a couple of wires coming off it. There are also wires coming from the oil pump. They all go to a module bolted to the side of the engine. That's the oil alert module. If you follow the 2 wires over the top of the engine from that module, they will go to a terminal block on the starboard side. One of those wires is 12 volts when the ignition is on. Test it to see if it's getting there. The other goes to the alarm. That one also has a wire that goes to an overtemp switch in one head. The alarm, buzzer, horn, light, or whatever is connected to 12 volts when the power is on, so there should be 12 volts there also when the alarm is not sounding. If you short that one to ground it'll sound the alarm if the horn is hooked up right. If shorting that one sounds the alarm, and the supply of 12 V is there, and the alarm doesn't go beeeep, beep, beep, beep when you power up, the alarm module is bad.

BTW, if power is always on the switched power lead, the alarm won't go through the test run. It only does that when the power goes from 0 V to 12 V. Sometimes a wire gets crossed hooking up whatever under the dash, and that line is powered from some other circuit. The alarm will still work, but it will kill the battery in storage, and not give you the warm fuzzy needed when you turn on the key.

Recap
The power wire should be 0 V with the key off, 12 V with the key on.
The alarm wire should be 12 V with the key on, and sound the alarm when grounded.

If that's all true, and it doesn't do the self test, replace the module. Otherwise fix the bad wire/switch.

hope it helps
John

 

[Diverted Income]

Re: silent alert horn

ok so the alarm module provides a path to ground for the alarm to sound.

 

[Laddies]

Re: silent alert horn

The beep you hear on startup is the oil module testing it's self when the horn does not beep on startup you ground the water temp sender all that does is prove the circuit that the 2 systems use on the engine through the wiring harnesses to the horn through the horn and to the switch back to the battery. I thought this was a simple question and a simple answer, I don't have a clue how it got so complicated. So If the horn don't blow when the tan wire is shorted to grd. and the key is on, replace the oil module to fix the problem.

 

[Diverted Income]

Re: silent alert horn

The beep you hear on startup is the oil module testing it's self when the horn does not beep on startup you ground the water temp sender all that does is prove the circuit that the 2 systems use on the engine through the wiring harnesses to the horn through the horn and to the switch back to the battery. I thought this was a simple question and a simple answer, I don't have a clue how it got so complicated. So If the horn don't blow when the tan wire is shorted to grd. and the key is on, replace the oil module to fix the problem.

That's easy, I was involved

 

[j_martin]

Re: silent alert horn

The beep you hear on startup is the oil module testing it's self when the horn does not beep on startup you ground the water temp sender all that does is prove the circuit that the 2 systems use on the engine through the wiring harnesses to the horn through the horn and to the switch back to the battery. I thought this was a simple question and a simple answer, I don't have a clue how it got so complicated. So If the horn don't blow when the tan wire is shorted to grd. and the key is on, replace the oil module to fix the problem.

Not quite that simple, but close. If 12 Volts switched power is not provided to the module, it will not test the alarm. Also, if the key is buggered up so that 12 volts is always there, it won't sound the alarm.

Check it out systematically, or buy extra, very expensive parts.

John

 

[Diverted Income]

Re: silent alert horn

Had a few minutes last night to check it out. Jumped the tan/blue wire coming from the high water temp to ground and got nothing. Time to open up the box and check it out.