Recently my tractor was left on (key in the on position) for and extended period (two days). I took it to a John Deere mechanic and they replaced the voltage regulator, the alternator, and the battery. One week after getting it back the battery discharge indicator light began staying on for 15 to twenty seconds after the engine started, and then it would go out. Took it back to the shop. Initially they said the glow plug was staying on to long and they thought it might be the module that controled the glow plug. They replaced the module but this did not work. They tested the battery, the voltage regulator, and the alternator and they are all operating correctly. I asked if they had checked the glow plug itself and they told me the had. JD is saying to use it till something fails then bring it back. I don't care for that option. Any ideas? Was a great tractor up to this point but now I am Frustrated!