No Engine Alarm buzzer when key is on

[Hans Baart]

Low Oil pressure switch is good, oil pressure at switch is good, continuity of yellow/white wire to buzzer is good. Buzzer works with test switch. Reason I’m asking this question is I cleaned my engine, removed and tagged all the wires to do so, put them back where they came from and now no low oil pressure alarm when key is turned on.

 

[Ralph Johnstone]

oil pressure at switch is good,

That statement doesn't fit. If you have pressure at the switch, no alarm. Please explain.

First question, do you get an alarm if you short the (+) wire at the switch to ground ?

The above is on a 2GM20F.

 

[Hans Baart]

That statement doesn't fit. If you have pressure at the switch, no alarm. Please explain. I

First question, do you get an alarm if you short the (+) wire at the switch to ground ?

View attachment 213507

The above is on a 2GM20F.

 

[Hans Baart]

Ralph,
I removed the pressure switch held my finger over the hole and oil squeezed out. I also checked the switch, I put my tester on the terminal and on the body while pushing the switch open by a long needle inserted in the end to open the switch. No buzzer when wire is shorted to ground with key on.

 

[JoeWhite]

See posting #2, short the wires to see if you get alarm. If you do, then bad pressure switch, not uncommon.

 

[Hans Baart]

See posting #2, short the wires to see if you get alarm. If you do, then bad pressure switch, not uncommon.

I did no alarm. Thanks

 

[Tally Ho]

Low Oil pressure switch is good, oil pressure at switch is good, continuity of yellow/white wire to buzzer is good. Buzzer works with test switch. Reason I’m asking this question is I cleaned my engine, removed and tagged all the wires to do so, put them back where they came from and now no low oil pressure alarm when key is turned on.

Do you mean when the key is on, but the engine is not running?

Greg

 

[Hans Baart]

Do you mean when the key is on, but the engine is not running?

Greg

Yes. Thanks

 

[Ralph Johnstone]

I also checked the switch, I put my tester on the terminal and on the body while pushing the switch open by a long needle inserted in the end to open the switch.

If I read you correctly, you had the switch in your hand and used a long needle to press against the open end of the switch. Did the resistance change when you moved the needle in and out of the switch. Not entirely clear here.

No buzzer when wire is shorted to ground with key on.

This appears to be the crux of the whole problem . The alarm MUST sound when the wire is shorted to ground BUT it doesn't. What is the voltage between the (+) disconnected wire and the ground ? This will tell us where to start the search.

 

[Hans Baart]

If I read you correctly, you had the switch in your hand and used a long needle to press against the open end of the switch. Did the resistance change when you moved the needle in and out of the switch. Not entirely clear here.



This appears to be the crux of the whole problem . The alarm MUST sound when the wire is shorted to ground BUT it doesn't. What is the voltage between the (+) disconnected wire and the ground ? This will tell us where to start the search.

I checked it but I checked a lot and can not remember. I will check when back at boat tomorrow. Thanks

 

[Hans Baart]

I checked it but I checked a lot and can not remember. I will check when back at boat tomorrow. Thanks

I checked it but I checked a lot and can not remember. I will check when back at boat tomorrow. Thanks

answer to your first part yes I had the switch in my hand and when I pushed the needle in the switch opened and the meter displayed no continuity. Thanks

 

[JoeWhite]

Do you have the wiring diagram for your boat? It will help tracking down the problem. On my engine this circuit is part if the fuel lift pump power. Did some wire come loose there?

 

[Benny17441]

The Test Switch only affects the engine temperature circuit to the buzzer which would otherwise not be activated by turning the key as the engine would not normally be in an overheated condition. Grounding the wire to the oil pressure sensor mimics the response of a good working sensor. Make sure there is power flowing to that wire when the key switch is turned on. You should have 12V to ground. If you have power and the grounded wire does not activate the buzzer then the buzzer has an internal problem and would need to be replaced. You could piggy back to the engine temperature sensor terminal and the buzzer should sound when turning the key, but if it activated while the engine was running you would not know if the problem is temperature or oil pressure. It could be a temporary fix. Them buzzers are expensive.

 

[leo310]

dose the buzzer even work? Mine failed.

 

[Hans Baart]

dose the buzzer even work? Mine failed.

Leo, The buzzer works when I use the test switch on the ignition panel. Thanks for the reply.

 

[Hans Baart]

The Test Switch only affects the engine temperature circuit to the buzzer which would otherwise not be activated by turning the key as the engine would not normally be in an overheated condition. Grounding the wire to the oil pressure sensor mimics the response of a good working sensor. Make sure there is power flowing to that wire when the key switch is turned on. You should have 12V to ground. If you have power and the grounded wire does not activate the buzzer then the buzzer has an internal problem and would need to be replaced. You could piggy back to the engine temperature sensor terminal and the buzzer should sound when turning the key, but if it activated while the engine was running you would not know if the problem is temperature or oil pressure. It could be a temporary fix. Them buzzers are expensive.

Benny, All good points I will check and try the piggy back when nectar the boat.

 

[Hans Baart]

Next

 

[Hans Baart]

Ralph Johnstown

This appears to be the crux of the whole problem . The alarm MUST sound when the wire is shorted to ground BUT it doesn't. What is the voltage between the (+) disconnected wire and the ground ? This will tell us where to start the search.

Ralph,
No there is no alarm when wire to oil pressure switch is shorted to ground.
Thanks

 

[Hans Baart]

With key on

 

[Ralph Johnstone]

No there is no alarm when wire to oil pressure switch is shorted to ground.

No, that's not the important part.

What is the voltage between the (+) disconnected wire and the ground ?

That will tell you almost the entire story of this Sherlock Holmes "Whodunit". Maybe a little more filling in around the edges, but this will tell you what's going on in there.