[PlatoSask]

One of our TR's is having some electrical issues, the buzzer only works for certain things. It works intermittently for full bin or stone trap but not all the time. The lights always come on but not the buzzer every time. I have noticed that the oil pressure sensor in the block is wired around but the other one on the filter housing is all good. Combine is new to us this year. The tachometer also works intermittently. Seems to never work at idle but often comes on when sped up. I am familiar with these combines but am looking for some insight before I tear the wiring all apart. I have read on here where someone suggested the oil pressure sensor in the block goes bad from vibration and somehow it powers other sensors... Not sure about this but I want it change it anyways and put a hose on it like our 98 to limit the vibration. Any experience insight or suggestions are greatly appreciated. Thanks all! Hope everyone's slugging er through!

 

[mike10]

The buzzer is replaceable. Remove the monitor and you will see it. The oil pressure sender is used to activate the relay for the stack valve hydraulics. It is the sender with two wires.

 

[PlatoSask]

I can see the buzzer is replaceable, but I don't think it's screwed. What do you mean the oil pressure sender is used to activate the stack hydraulics? This sender is wired around, all hydraulics work fine. Thanks for the reply.

 

[makar]

I have the same problem and its not the buzzer, I think maybe monitor issue. My pressure sensor works on and off but everything else stays the same. The buzzer for the gauges is a different circuit.

 

[mike10]

I can see the buzzer is replaceable, but I don't think it's screwed. What do you mean the oil pressure sender is used to activate the stack hydraulics? This sender is wired around, all hydraulics work fine. Thanks for the reply.

The oil pressure sender with the two wires is a normally open switch, in other words when there is no engine oil pressure the circuit between the two terminals on the oil pressure sender is open and no current can flow. Once there is engine oil pressure the sender closes and completes the circuit which in this instance the sender is completing the ground circuit for the run relay in the cab. With the circuit completed the run relay is energized and current is sent to the switches which operate the hydraulic functions of the stack valve.

Since your sender is wired around the ground circuit is complete and that is why your hydraulics work.

 

[PlatoSask]

Ok Mike10, thanks for your help. I am going to replace that oil sender after harvest. I think I will clean up the common ground for the monitor stack. Ground always seems to be a good place to start anyway.

 

[PlatoSask]

Also the tach is really bugging me. The display always lights up but sometimes reads 0, usually upon start up. If you rev the engine up a bit the tach usually displays the proper reading, although sometimes you can thrash half the day without it displaying engine RPM. Any input is always welcomed. Thanks all.

 

[mike10]

Probably the engine speed sensor on the back of the engine bell housing.

 

[PlatoSask]

Ok, I will check that. Thanks Mike10! Is there anyway to test the sensor?

 

[mike10]

The ohm reading for the sensor should be 2550 +- 250 ohms