Quick question on thesting the "hot" horn

[05blastsrt4]

Hello all I have a 1971 Johnson 60hp, I am wanting to test the hot horn can someone tell me how to do this I am attaching a picture of the wiring diagram.

 

[seahorse5]

Re: Quick question on thesting the "hot" horn

with the key ON, ground out the tan wire in the engine harness that connects to the temp switch on the cylinder head. The horn should sound if everything is operational.

 

[05blastsrt4]

Re: Quick question on thesting the "hot" horn

thanks for the info exactly what I was needing

 

[Wishiniwuzfishin]

Re: Quick question on thesting the "hot" horn

That tan wire should have a blade type connection covered with a rubber sleeve over it somewhere near where it comes out of the cylinder head(shown in the wiring diagram near the temp. switch). Slide the sleeve down the wire and the connection easily comes apart. Makes it easy to check as seahorse sugggested. Make sure you ground the right side of the wiring and BE AWARE: this test does not actually test the function of the temperature switch. Just shows the horn is working. Temp switch could still be defective and horn might work, but the system would still be defective, meaning you would not get a horn sound if motor overheated.

 

[05blastsrt4]

Re: Quick question on thesting the "hot" horn

That tan wire should have a blade type connection covered with a rubber sleeve over it somewhere near where it comes out of the cylinder head(shown in the wiring diagram near the temp. switch). Slide the sleeve down the wire and the connection easily comes apart. Makes it easy to check as seahorse sugggested. Make sure you ground the right side of the wiring and BE AWARE: this test does not actually test the function of the temperature switch. Just shows the horn is working. Temp switch could still be defective and horn might work, but the system would still be defective, meaning you would not get a horn sound if motor overheated.

Thanks for the tip , Is there anyway of testing the actual temperature switch?

 

[Wishiniwuzfishin]

Re: Quick question on thesting the "hot" horn

Yes but it involves removing the switch and immersing it in very hot water to test at what temp it closes.

The temperature switch is actually just an on/off switch that is off (open) with a cold motor or motor that is under the temperature that the switch is set for. When it is open, the power circuit to the horn is not complete.

When the motor gets too hot (whatever temperature the switch is designed to close at), the switch turns on (closes) and completes the power circuit to the horn, making the horn sound.

To test the actual switch you have to remove it from the motor and immerse it in water that can be heated and has a thermometer in it so you can see the temperature of the water. As you heat the water and note the temperature of the water, you either visually look for the switch to close or use an attached voltmeter or circuit tester to note when it closes. The temperature can be compared to what the switch is supposed to close at, telling if the switch is closing properly.

I think most people just replace the switch rather than testing if there is any doubt as to whether it's working or not.