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Battery discharge indicator light. Stumped. X495

6544 Views 2 Replies 3 Participants Last post by  gotdeeres
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!
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Sorry for you problems. I would maybe find a diff. dealer. I could see the battery being shot but not the other stuff. Sounds weird that the voltage reg. and the alt. would go bad because you left the key on.

As for the light that is strange. I don't blame you for not wanting to wait for something to fail. Good luck and hope you get it sorted out!
Initially, a few simple voltage measurements could have ruled out the battery, rectifier, and alternator. The fact that the problem started after it was left on is a mystery to me. My SWAG is there is a shorted glow plug or a short in the wiring to the glow plugs. Each glow plug draws 10 amps of current and with three that would be 30 amps which is a pretty substantial amount of current.

The A1 Diesel Controller powers the glow plugs when the ignition key is in the RUN or START position. The Glow Plug dash light indicates that the glow plugs are preheating the cylinders and turns the light off after about 10 seconds. The light turns off, but the controller continues to heat the cylinders even after the engine starts for about 20 seconds.

Since the Discharge light stays on for 20 seconds, I suspect the glow plugs or wiring. The alternator is rated at 20 amps and the glow plug drain is 30 amps. This is why the light remains on with the engine running until the glow plugs turn off. To test the glow plugs:

1.) Start and warm up the engine. Shut down the engine.
2.) Disconnect the white lead to the glow plugs.
3.) Start the engine and verify whether the Discharge light remains on after the engine starts.
4.) If the Discharge light turns off, the problem is with the glow plugs. If the Discharge light stays on for the additional 20
seconds, the problem is a short to ground in the wiring to the A1 Controller.
5.) To test the glow plugs, disconnect the wiring between the three glow plugs.
6.) Test each glow plug with an ohmmeter. Ground the black ohmmeter lead and put the red lead on the electrical terminal of the glow plug. The resistance should be around ONE ohm. If there in high resistance, the glow plug is open. If there is zero resistance, the glow plug is shorted. In either case, the glow plug needs to be replaced. Normally a glow plug willl open rather than short circuit.

Just a wild guess, but that is the only thing JD did not change.

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