Why is my glow plug light blinking when the John Deere 8960 is running?
Check the codes. Typically a flashing spark plug light means there is a code from the ECU.
The first thing you would do is check the fuel filter / water separator for the water. Even a little water will make the light flicker. Power will also be reduced if there is water in the fuel.
It is an easy thing to check, and it may solve your problem. Otherwise, you may need to check the codes with your Service Advisor.
You may also want to check all your filters for problems.
I have a John Deere 8960 that did the same. I thought it was a bad sensor for water in fuel, but it turned out to be a broken wire at the injection pump. I think it was a fuel temperature sensor. The engine never crashed. I put a connector on it and closed it to prevent it from moving and breaking again.
Cleaning the cooling system takes care of this, along with making sure the coolant level is good. I’ve never seen a tractor that needed so much cleaning of the radiator and coolers, and we don’t run it on dirty air.