Logo
FULL SITE MENU

2002 90 hp Mercury outboard high heat alarm relay

S

Stressfree

Member
My alarm goes off when key is turned on book says unplug heat sensor if alarm stays on move on.book says bad alarm relay or grounded out wire.any ideas
 
The Horn is in the remote control or under the dash. On one terminal is 12v switched from the ignition switch in on-start. The other terminal goes via the tan/light blue stripe wire to the 8 pin connector in the engine, pin 3.

The engine side of pin 3 goes 2 places, each connecting to ground if the circuit is closed: The OT warning horn buried in the water jacket cover on the rear of the block, and the oil tank float switch, closing when the oil level has dropped to around 1 quart remaining. Both are wired in bayonet connectors and can be separated right there at the engine to remote cabling connecting area.

There is no relay, just what I said. If you unplug both from pin 3 bayonet pigtails within the engine and the alarm stays on, you have a short on that sense wire to batter(-) somewhere in your cabling to the engine, within the control itself, if horn is mounted there, or under the dash if mounted there.
 
I could ring out brown wire to engine from horn not much room from cable in engine.merc book says it had a alarm relay that's why I said that.
 
Your right printed out wiring diagrams should be a Home run to horn I’ll check for bad wire it looked like the wires went into the small black relay there
 
The magnet inside the oil tank wasn't one of Mercury's finer moments. I had mine fall off last outing and I'm not going to saw my oil tank in half and attempt to satisfactorily glue it back together to get at it......sometimes the cure is worse than the cause. I have a reminder to check the tank oil after each outing.
 
Texasmark said:
The magnet inside the oil tank wasn't one of Mercury's finer moments. I had mine fall off last outing and I'm not going to saw my oil tank in half and attempt to satisfactorily glue it back together to get at it......sometimes the cure is worse than the cause. I have a reminder to check the tank oil after each outing.
Click to expand...

this is the high heat alarm my oil is on the side this one screams the oil chirps also has the brown/blue wire
 
Got a chance to look at it I was wrong both high heat and low oil share the same horn both have a series circuit to ground so what do I do with the low oil alarm change tank
 
I was able to re glue my magnet back onto float. I made tools out of rod to pull spring washer off. Cleaned and JB weld mag. Been working for 4 years.
 
Back
Top