1989 evindude 90hp freshwater overheat alarm

1989 90hp overheat alarm , stays on when I turn ignition on with out motor running at all .I have checked all connection's on motor all are good .In control box where all the wires come back to are also good by ignition .Have replaced water pump last fall , steady stream out of motor.This has been an intermittent problem the horn will stay after running and sometime's it will shut off by itself , then on next start up it will not come at all . HELP!!!!!!!!!!!!!!

Re: 1989 evindude 90hp freshwater overheat alarm

When you turn the key to the ON position (engine NOT running) and the horn sounds off, remove the TAN wire from the horn.

If when you remove that TAN wire, the horn continues to sound, the horn is faulty... replace it.

If when you remove that TAN wire, the horn shuts down immediately, either that TAN wire is grounded out somewhere OR (and most likely) one of the sensors at the engine (VRO electric plug, Heat sensors (2) at the cylinder heads, Oil tank connector at engine) has failed.

If a sensor failure, with the horn sounding, simply start disconnecting the sensor wires until the horn shuts down, at which time you've found the offending sensor.