John Deere 4100 Hst went from running well with load in bucket to not starting..after

[parrot24]

Hi, I have a JD 4100 1998 had an issue with the battery going dead after running the tractor.
A friend of mine took the tractor had it for 2 weeks checking the electrical system almost gave up.
1 last check the relay that powers the glow plugs was bad keeping full power to the glow plugs killing the battery. Changed the relay havn't had a problem since. Looks like your problem is fixed but if it happens again you'll have a place to look. We couldn't find the relay on the tractor it's up near the battery on top. Hopes this helps. Norm

 

[projectgator]

Hi, I have a JD 4100 1998 had an issue with the battery going dead after running the tractor.
A friend of mine took the tractor had it for 2 weeks checking the electrical system almost gave up.
1 last check the relay that powers the glow plugs was bad keeping full power to the glow plugs killing the battery. Changed the relay havn't had a problem since. Looks like your problem is fixed but if it happens again you'll have a place to look. We couldn't find the relay on the tractor it's up near the battery on top. Hopes this helps. Norm

Norm,
Thanks for this information. I felt fairly certain that was my problem when this started, or excuse the pun, when the tractor didn't start! The hard part for me to understand is that the tractor went from starting and running without an issue to running and then on re-start nothing. The tractor has always "amped" up with the turn of the key prior to starting...until it did not. Additionally, the batteries I tried jumping tractor with were apparently bad so it was difficult to get a real decent read on the issue. As we speak the tractor with the new battery and new postive and negative battery cables is running like a champ. I will look for the relay...just for insurance sake. Thanks for your input!
Regards,
Rick

 

[woordpecker]

Hi Projectgator:

We've just begun having a similar with our 4100 of similar 'vintage', and found the following info on other posts from two tractor forums. You may want to tuck this info away for future reference?

Rgds, Woordpecker

J-D 4100 Compact Tractor –

Problem – new battery does not appear to be charging, motor died while grass cutting.

BELOW ARE QUOTES FROM THIS FORUM AND ANOTHER ONE:

“Well I finally received the tech manual today, too many pages in the Electrical system section and not enough time left in the day to go thru it all, so I did what most guys do, looked for the quick test/fix. After 3 hours of testing components and analyzing the schematics and not finding a bad part, I switched the "K7 Safety Relay" with the "PTO Light Relay" (because they look identical) and the charging system started working. Oddly enough, the PTO system appears to be working fine also. So my best guess to the problem is the relay was/is partially damaged from either the battery cell popping or the voltage surge. Although it was still passing current thru, it was not enough to turn the voltage regulator on to charge the battery. I also put the old voltage regulator back in and it works fine, $140 wasted.

“Update: I tested the relay that was in the charging system (per the tech manual) and it is fried. The reason it worked in the PTO system is that system is an "open" system, and under normal conditions the relay is not energized. The charging system requires the relay to be energized to close the circuit and allow charging. I also did a search for the relay because John Deere wanted $90+ for it which seemed a little pricey to me. I found a cross reference to a Subaru Starter Interupt Relay, and ordered it thru the Subaru dealer for $42. It is identical. Who knew an Auto dealer would be the cheaper alternative?

The Subaru P/N is H7110AS930 and I believe it was called a Starter Interrupt Relay. The AC voltage coming directly off the alternator is 28-35 volts at a nominal engine speed, at full throttle it is closer to 50 VAC. At the battery or anywhere after the regulator it should be 13.5-14.5 VDC regardless of engine speed. When my relay was fried, the battery charge light never came on, which is why I wasn't sure what was wrong. After I replaced the relay however, I noticed the Batter Charge light is supposed to be on when you turn the key on, and go off when you start it.”
__________________

 

[RitchElbe]

Every time I have had this happen..sudden loss of power. I found the connection to the alternator to be a bit dirty. Once cleaned....runs great again!