I have a problem with a 200LC John Deere I need help with. It won’t crank and when you turn the key off after trying to crank it the battery relay stays energized. I have determined the alt shut down relay and starter protection relay are staying energized thru a ground signal coming from the monitor. I have more information if anyone can help
See if you can find somewhere to bar the engine over. Crankshaft, Flywheel, whatever is easily to reach. It is important to rule out a seized engine.
Does it click or anything when you try to start it? I've had to replace a bunch of those main relays on those exact machines.
It will crank if I unhook the alternator excitation resistor. I am getting battery voltage to the monitor pin 42 when the key is turned on.
I'd say replace the alternator. Had a JCB do that exact thing to me once.
It’s getting voltage back to the monitor but it’s not coming from the alternator.
Right, but it's getting a signal from the alternator that's telling it not to start.
No I unhooked the D+ wire that would send the signal when the machine is running
Remove the D+ wire from the alt and ground it and see if it starts. The monitor needs to see a ground from that wire or it won't crank.
That was it !! I used a test light to check the D+ and it cranked. Thanks for the help
Did you ever get it sorted out? Grounding the wire will make it start but battery light will be on.
It seems like with key on engine off should be getting like 8-14 volts on d+ not 20+ volts could this just be the resistor out of spec?
It gets a ground signal from the alt thru the D+ wire. When the machine cranks the D+ give system voltage and the light goes out
I hope that's it I just have issue believing that a bad alternator can cause a no crank. but maybe it was a design flaw because the c model it's separate the excite circuit from charging light indicator. New alternator shows a separate resistor that goes from b+ to d+ making it self excite. Going to see if dealer has any paperwork with updated alternator
That alternator should have come with paperwork. What part number alternator did you get? @Diesel Dave might be able to help with this. Add the serial number of your machine as well.