How to Test A Temperature Monitoring Alarm Switch

[San_Diego_SeaRay]

I have a ~1993 Gen V Bravo 7.4 engine I'm working on. I'd like to make sure that the Temperature Alarm system is working properly. I know that the Oil Alarm works off of a normally on circuit, so that when you put the key in the ignition the oil alarm circuit is "ON" and so you hear the buzzing right before starting the engine. And then you turn the engine on and the oil pressure increases, the switch turns to an OFF mode, and the buzzer stops buzzing. So it's easy to tell that that circuit is working.

However, the Temp Alarm Switch works off of a normally off circuit. So that when you turn the ignition switch on, the Temp Alarm circuit is off. It's only if you reach a specified temperature (180 degrees?) does the temp switch ground out and the circuit is completed and the buzzer sounds. So my question is how can I test this circuit so that I know it will reliably trigger if needed?

 

[GA_Boater]

Connect a meter to the sensor on ohms scale, dump it in a pot of water with a thermometer and turn on the gas. See what temp the sensor closes.

 

[alldodge]

Agree put in a pot of water and place a thermometer in the pot. You will either have one of the two senders listed below, but being a 93 its probably the 48952

Temp switch 87-866089 or 87-86080
175 to 195 degrees and lower it should be open
215 to 225 degrees and above it should be closed
Temp switch 48952
150 to 170 degrees and lower it should open
190 to 200 degrees and above it should close

 

[San_Diego_SeaRay]

Connect a meter to the sensor on ohms scale, dump it in a pot of water with a thermometer and turn on the gas. See what temp the sensor closes.

It doesn't get much simpler than that. Thanks!

 

[Alumarine]

I'm not sure if it matters but when testing a sender or thermostat I suspend them and the thermometer so they don't touch the bottom of the container.

 

[Bondo]

However, the Temp Alarm Switch works off of a normally off circuit.

Naw,... They're actually both on the very same circuit,.....

They're both switches that go to ground,....
No need to ohm it, it's grounded or not,... a switch, not a sender,....

Ya hear the oil pressure alarm, 'cause when the motor ain't Runnin',....
There ain't No oil pressure,....

All the alarms are always On, with the ignition switch, just wiatin' for a ground connection,...