Re: johnson 88 hp temp sender
The 1988 remote control did not have the horn that performs a test beep at start up. It did have a slot above the ignition key into which you could insert a spare key to test the horn with the ignition key in the run position.
Neither tests the temperature switch at the engine or the wiring between the horn and the temperature switch.
To test the wiring, disconnect the tan wire at the cylinder head and ground the control ends of the wires to the engine block; the horn should sound if the ignition key is in the run position.
To test the temperature switches will require removing the water covers from the cylinder heads and prying the switches from the blind holes in the cylinder heads. You can then attach an ohmmeter to the switch, immerse the switch in oil, and heat the oil to around 210 degrees at which time the switch should close and show a reading on the ohmmeter.
