How do you check the temp sensors

[scb2377]

I have a 1987 Johnson 88 SPL. I found the following info on checking the temp sensors:

"Test the overheat warning system by having the key in the ON position (engine not running) and then ground out the heat warning sensors at the cylinder heads one at a time. The horn should sound off each time you ground either one. If not, find out why as that's the only warning you'll receive."


Is this info correct and if so can someone give me a little more detail on how to do it? Thanks!

 

[rob711]

Re: How do you check the temp sensors

the sensors are on the top of the heads....look like plugs w/a wire comming out....follow the wire bace to where there is a black rubber cover over it...slide the cover down the wire...now touch the wire to the block..with the key on it should sound the horn....good luck

 

[Silvertip]

Re: How do you check the temp sensors

That test verifies the warning horn works. It does not verify the overheat sensors actually work. If you are getting a solid horn, disconnect that tan wire and the horn should quit. Now you can use an ohm meter to test the switch. Red lead on the tan wire and black lead on ground. Continuity you have switch closure. Open circuit the switch is open. If the switch is closed on a stone cold engine its bad.