Glow plugs are gone at 540 hours

[ptsg]

Is there any sensor which commands when to turn it on/off? i could not find one. Sorry for the ignorance

There is actually two temp sensors on the engine. One for the instrument cluster and the other one is used for the glow plug controller so it knows the coolant temp and adjusts the preheating and after-heating times.

Here is a little graph that shows how much time it runs:

 

[ruffdog]

If the GPs don't shut off, I wonder if the problem could be the ign switch. If the ign switch activates the relay that turns on the GPs, maybe the SW is bad?????

 

[2515R Dude]

There is actually two temp sensors on the engine. One for the instrument cluster and the other one is used for the glow plug controller so it knows the coolant temp and adjusts the preheating and after-heating times.

Here is a little graph that shows how much time it runs:

View attachment 4557254

Great, thanks for the info. It should be some chip/processor to run this algorithm. I thought this tractor as simple as a hummer.
I'll check it tomorrow and report back.

Good thing, now it starts right up with no problem. I have a huge red oak tree fall 20 ft from my house and could not do anything because the tractor would not start. Temps were in low 30th.