John Deere 4100 electrical/no start issue

[Rdmmo]

Looking for some advice on my 1999 John Deere 4100 HST. When key is in the on position everything is fine, lights work etc. when I turn they key further to start the engine, it may turn over a few times but the fusible link on the starter blows immediately. Battery connections and grounds to frame are all good. I've looked for bare wires everywhere and can't find anything. Checked seat safety switch, PTO switch etc all good. Any help would be greatly appreciated. Snowing and blowing here and I need to get to work. Thanks!

 

[beenthere]

Maybe begin by removing wires and cables one at a time and tracing the voltages to find out where the problem lays.

 

[/pine]

Sounds like the starter...especially if it is the only thing on the fuseible link

 

[Tx Jim]

Sounds like the starter...especially if it is the only thing on the fuseible link

Ditto. I suggest to attempt to check amp draw on starter while engaging starter.

 

[mike48130]

Internal short on the starter.

 

[Phillip w]

Everyone done picked my diagnosis: internal short in starter.

 

[Rdmmo]

Hmmm. Just not sure it's in the starter because it will turn over and seems to work well before fusible link pops

 

[oldnslo]

When the fuse pops use a volt meter to check resistance to ground. Dead short would read zero

Bad connection could also cause excessive amp draw which would trip the fuse.

 

[mike48130]

Put a clamp on amp meter on the power cable and see what it's drawing. Either you have a starter motor going bad, some kind of short, maybe a bad connection or the engine is binding and causing a heavy load. Could be a binding alternator or water pump.

 

[Rdmmo]

Everyone done picked my diagnosis: internal short in starter.

Starter is good. Removed and had it load tested and everything checked
out fine

 

[mike48130]

Looking at the schematic in the post below, it looks like the fusible link is before the switch, and powers several circuits. You could probably start pulling relays and connectors on these other circuits to see if one is having a high load. The post talks about voltage regulator issue, so maybe you have a similar issue.

http://www.tractorbynet.com/forums/...33021-jd-4100-voltage-regulator-meltdown.html

 

[Rdmmo]

Just getting back to messing with this 4100 no start issue. Pulled starter and had it checked. Operated fine during load test etc. I can’t find a short anywhere. Only wire that gets hot to the touch is the fusible link and then it pops after the motor turns over 4-5 Times. Loosened alternator so no binding there. water pump doesn’t seem to be bound up.

 

[Rdmmo]

I disconnected the glow plug relay and no difference. I will have to try and locate the K3 relay. No manual etc. Thanks.

 

[beenthere]

Rd
Here is screen shot of location that may help.

 

[Rdmmo]

Thanks for posting. Very helpful! I disconnected K2 and K3 with no change

Coincidentally, before I disconnected the relays I tried to start it and the ole 4100 started right up and ran like a dream. Fusible link wire was ice cold and never got hot at all the while it ran. Regrettably I shut it off and haven’t been able to duplicate it. Now when I try to start it, even with the relays unplugged, that fusible link wire gets red hot as it has been......

 

[Zebrafive]

I would disconnect the wire from the key to the starter. If the fusible link still blows, it's not the starter.

 

[Rdmmo]

I also disconnected the voltage regulator and tried it and that made no difference either

 

[Rdmmo]

I had previously taken the starter off and took it in to the auto parts store and had it load tested and it operated perfectly fine. Ran it numerous times. I also changed the key switch to a spare one that I have and that made no difference.

 

[Rdmmo]

I unplugged just about everything with no changes. I ordered a starter. Thinking I’ve got something weird going on with it even though it tested ok awhile back. It’s not turning over like it was. I’m hoping that’s it

 

[Rdmmo]

That’s what I was determined it was as well but I can’t find anything anywhere. I’ll continue to look. I checked all wiiring disconnected, cleaned and retightened all ground connections on the frame that I could find. I’ll carefully double check the positive cable again. Thanks