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How to test oil and temp alarms on 1988 454

R

rmm

Regular Contributor
"Want to check my alarms to ma

"Want to check my alarms to make sure are working as just did a lot of dash rewiring. The oil alarm sounds when turn key but don't start yet, so assuming that works, correct?

How can I test the temp alarm? I tried removing the wire from the alarm sender but nothing happened.

How can I test these? Thanks"
 
Try grounding the sending unit

Try grounding the sending units. Just connect a wire to ground then tap the connections on the sending units. Should get an alarm if the wiring is correct. Be careful not to gound them for too long though. You didn't mention engine model and some engines will reduce RPM or shut down on alarm.
 
"The only way to be sure your

"The only way to be sure your temp switches are working is to pull them out and test them. Stick them in a bucket of boiling water, put a volt meter on the contacts, and see if the contacts close as the switch heats up.

Note: On my boat, 3 out of 4 temp switches I was depending on (that had been there for 20 years) did not work! The result was a blown motor when the water intake got cut off (plastic bag? floating rag?) I now run NEW temp switches (automotive type bought on Jeggs.com) and will be testing these next year as part of my Spring Commisioning procedure.

The bottom line: Trust not without verification!

Jeff"
 
"Grounding the sender wire wil

"Grounding the sender wire will test the system, but it will NOT test the sender. As Jeff stated, there is only one way to test the sender."
 
"Best way is like Jeff said. T

"Best way is like Jeff said. To clarify, the switch closes when it gets hot. It should come on at 200 degrees, at least for Marine applications. Some auto applications will turn on at higher temps. If the switch closes with boiling water (212 degrees at sea level), you have a good switch.

Your description of the system indicates the oil pressure switch is functioning. Like Rick said, grounding the sensor wires turns on the horn. It is a good idea to do this when you pull the temp switch to check as they are usually at the end of the circuit."
 
Thanks guys. When you say cont

Thanks guys. When you say contacts do you mean the single screw post the wire is connected to. Also will the volt meter register if no power to it? What should the volt meter be set to? Could describe this in a little more detail?

Sorry not real versed in electrics. Thanks
 
"IF the switch has a single co

"IF the switch has a single contact, then you connect it to one lead of the ohm meter, with the other lead going to the shell of the switch. (That's the mose common type.) Some switches have two contacts; in that case you connect across the two with the ohm meter.

Note: An ohm meter senses if the circuit is open or closed.

Jeff"
 
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