Overheat Alarm Wiring

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Tampa Nick

Cadet
Joined
Feb 29, 2012
Messages
8
Motor is a 1996 Johnson 112 spl

I noticed that I had no chirp from the alarm when I turned the key to on. I pulled the alarm and hooked it directly to a battery it did nothing.

I picked up a waterproof piezo buzzer from RadioShack and hooked the purple wire to pos and tan to neg. I just get a constant alarm when the key is on

I tried wiring the black wire that was attached to the original alarm to a ground and also to the neg terminal on the new alarm but it still has a constant alarm

Anyone have any ideas or suggestions?

Thanks
 
A

andrewddrennon

Seaman
Joined
Jan 17, 2011
Messages
73
Re: Overheat Alarm Wiring

There should only be a purple and a tan attached to your warning horn.
When the motor overheats the tan wire provides the ground for you horn through the temp sensor. With the key on unlpug the tan connector just before your temp sensor on the head. If the alarm stops the temp sensor is bad. Motor isnt running right?

Purple+
Tan-
 
metriccrescentwrench

metriccrescentwrench

Commander
Joined
Oct 22, 2007
Messages
2,598
Re: Overheat Alarm Wiring

Tampa Nick said:
I picked up a waterproof piezo buzzer from RadioShack and hooked the purple wire to pos and tan to neg. I just get a constant alarm when the key is on
Click to expand...

When the key is on that purple wire is always hot.

The "ground" side of the alarm buzzer goes to temperature switches in the head (or at least it's supposed to) which are normally open . In an overtemp condition one of the temperature switches will close, completing the path to ground for your buzzer. SO, if you're always getting the buzzer either the ground side of the buzzer is connected directly to ground or else one of the temperature switches is bad.
 
T

Tampa Nick

Cadet
Joined
Feb 29, 2012
Messages
8
Re: Overheat Alarm Wiring

So do I not need the black ground anymore? It came directly out of the old alarm

Motor is not running, but key is on

I have two sensors it looks like. One on each of the bottom cylinders. Should I check both? Is there an order?



Thanks
 
A

andrewddrennon

Seaman
Joined
Jan 17, 2011
Messages
73
Re: Overheat Alarm Wiring

Not sure what the black ground would have been for? Anyway yea check both sensors.
 
clanton

clanton

Rear Admiral
Joined
Jul 9, 2001
Messages
4,876
Re: Overheat Alarm Wiring

The ground wire in the diagram is for the OEM horn that will self test, when you turn the key on.
 
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