Hey y'all. I am stumped on the John Deere 250 Skid Steer we have. It is an older one, serial number is KV0250A151500. I am on the second new alternator for it, first one was warrantied due to not charging, so I doubt my luck is that bad for the alternator to be the issue. Belt tension is good. Battery is also new. I have whatever the battery voltage is at the + and - on the alternator. I fire up the machine and voltage does not change, it will slowly decrease while it stays running, obviously, but will not charge the battery still. What could be the cause? I need this machine back up and running well. I have tried reading forums and watching videos to check other possible issues. I have no schematics for it, nor will the local dealers help me find some. Thank y'all!
Does it have only the Battery output post on it or does it have some control wires hooked up on it. A picture would help me and others who have worked on them lots to figure out cause. Do you know how to do a load test of the positive output cable that goes to batttery Positive at the Starter solenoid or at the battery itself.? Is it a OEM alternator or cheap from China.? Not saying it is no good, just wondering. Some alternators lose their magnetism and just have to be sparked for a second while running to get them going again. Post some pictures if you are able to and I will think about it while waiting. Simon C
New now days dies not mean good. Can have more than one bad "new/reconditioned" alternator
I've attached photos of the hook ups on the back of the alternator per how our local equipment company told me to hook them up since the old alternator had fewer terminals on the back. There is a positive and negative cable and then one wire that splits to two and goes into the wiring harness, ive been tracing that as well so check continuity. I can look up how to do a load test and try that out. The positive battery cable goes to the starter than to the battery. It is an OEM one from our local equipment store. Should I try jumping it to kick it into charging mode? How would I jump it I'm off work shortly so Ill get back to you again first thing in the morning and start the load test.
I figured that would be the case with the first alternator and I'm not saying its not the case now but the chances are slim so I wanted to rule out any other issues that could be causing it to not charge before I had them warranty an alternator again. The machine is old and abused so I wouldn't be surprised if it was something else that was the issue.
Dang dealers (eye roll) . See 4 screenshots of the Deere 240/250 electrical schematics below from manual TM1747 . . . . . .
According to wire diagram, there should be 2 wires attached to the D+ terminal, one of those wires (Brown) goes to instrument cluster,(Charge light) I would assume. the other (yellow), ties into the accessory relay load side, (exciter wire) I would also assume. Not positive, but something to check. You have nothing attached to D+ terminal.
Yes Arny is correct, you have it wired wrong. Your bottom picture has the end of your finger beside the D+ ( terminal ) with nothing hooked up to it. #1 The 600Brown wire hooks straight up to that terminal. #2 The 452Yelow wire feeds through the Alternator resistor to the same D+ ( Termiinal ) #3 There is a big RED wire that goes on the B+ Terminal that goes to the Starter Solenoid Positive Post ( Large Stud ) #4 There is a big black wire that you already have on the Battery Negative terminal of Alternator that goes to Battery Negative post or to a Good frame connection. The schematic showed 2 wires going to ground off of that stud. #5 Hook up Like this and it should run. And before I forget thanks to Diesel Dave for providing the Schematic. Simon C
Dave can sit next to Lachau for his free meal on us.
Good morning! The brown and yellow wire go to a "wiring harness" as the parts describe it. The local equipment store had me hook that harness (the thin red wire in the photos) to the W terminal where its at in the photos. Since it wasn't charging I did some research on the terminals, I did move it to the D+ terminal as that's where I believed it should be hooked as well and there was still no charge at all. I moved it back before the taking the photos for y'all so that it was at the original location that I was told. I have moved that wire back to the D+ terminal. I tested Relay K4 per the schematics and it is functioning properly. I also have continuity down the wire from B+ to the relay. I am still studying the schematics.
Thank you so much for these! Its helping tremendously!
I have tried hooking those wires to the D+ terminal as well and still getting no charge. See reply up above to Simon. Also thank you for everyones help!
How about sending us a picture of what is hooked up now, and we can evaluate. Simon C
I did noticed that I keep blowing the 5 amp fuse each time I start the machine. Per the operators manual that 5 amp should be a seat switch. But the wire going to it has continuity to terminal 30 on the accessory relay. Which per the schematics we should have a 25 amp relay going to that relay terminal but none of my fuses are 25 amp. Could be possible that the wrong fuses are in here? Back story: the skid steer is old as dirt and the mechanics prior to me were not great mechanics to begin with especially when it came to heavy equipment or vehicles.
What’s under that clump of taped wires, just behind the D+ terminal. Former repair, always suspect. Just to eliminate a potential issue.
It is this "wiring harness" as JD calls it not a repair. That was my first thought as well though. The brown and yellow wire that go to D+ plug into this and this hooks to D+. I did check for continuity through it and have it to both wires.
Per the schematics the wires I have going to the fuse should be (top to bottom) by the colors of wires going to them. F3: 15 amp - key switch F2: 5 amp - seat switch F1: 25 amp - Accessories F4: 5 amp - Interlock fuse So my fuses were definitely mixed up. I correctly placed the fuses but my accessory fuse, which is the circuit for my alternator, immediately blows once I put the fuse in, indicating a short somewhere is that circuit?
Unplug the cold start advance at the injection pump as well as the coolant switch for that cold start advance circuit and see if your fuse stops blowing.
Post number 14 bottom picture shows two ( D+ ) terminals. I am wondering if the 600Brown wire is suppose to go to the Male spade that you can see just below the ( D+) that has a wire hooked up to it. Think something is hooked up wrong. What is the plastic white plug on the top picture of Post #14. Simon C
Did that alternator come with a schematic, may help to figure out. Simon C
What if you disconnect D+wires to alternator, see if it blows fuse. If it doesn’t, then it’s possibly that alternator wire.If it does, there are 3 other circuits powered by that accessory relay, one goes to dual flasher, one goes to cab heater relay, one goes to backup alarm.
Simon - no the alternator did not come with a schematic. The brown and yellow wire connect to the resistor (the melted looking piece the JD calls a wiring harness in the parts) and then only one wire comes out so it can only connect to one spot on the alternator. I can try plugging it into the other D+ terminal. It could be the fuse being blown causing the alternator to not charge but some where in the circuit we are shorting out blowing the fuse before even starting the equipment? Arny - I unplugged the wire at D+ and still blew a fuse. Im going to check the other lines now.
That melted looking piece should be opened up and checked inside in case something is wrong. And what about the white plastic plug that we can see in Post#14 top picture. Is it loose or is it plugged into a spade. Simon C
It look like someone covered it with a silicone honestly, will probably need to be replaced just to be safe. The white plug on the alternator came on the alternator already plugged in like that.
So from port 86 on the K4 Accessory Relay, wire 550 goes up to the key switch. I unplugged that wire from the key switch and can now put a fuse into that circuit without blowing immediately. Could a faulty key switch that's shorting out internally cause my fuse to blow and in turn my alternator to not charge? There is continuity in wire 550 from where it plugs into the key switch to the relay with minimal/ no resistance. I attached photos of the wiring. It could have been shorting out just with the crappy wiring job for the plugs.
That's pretty nasty wiring. It supplies 12v to 86, leave it unplugged from ign sw, and feed it directly with 12v from one of the other terminals, by passing ign sw internals. try not and short anything out.
With blowing fuses I think you have more going on and not sure if this would help with that part but… I chased a no charge on my 580SL Case and after lots of diagnosis and several parts I found that the charge light on the dash is part of the circuit and function for changing and with the bulb being blown caused the no charge issues. Check your schematic. Does the bulb illuminate for the test when the key is first turned to the run position?
If you are immediately blowing a 25 amp fuse, then you have a hard short circuit somewhere. Take all the wires off the alternator and see if the fuse still blows. If it does, the short will be in the wiring somewhere between that fuse box and the alternator. If the fuse doesn’t blow, hook up one alternator wire at a time until it blows the fuse. That will be the grounded wire you need to track down.
That's true about the charge light, but the resister is there to simulate the load the bulb provides, in the event of a blown bulb. But yes, it will not charge with a burnt bulb, and I don't think that was ever established.
If the fuse blowing started with the alternator installation, then ignore this. if it was something you just discovered, then did you check the cold start switch and the cold start solenoid like I mentioned in post #19? Those items are known for blowing the Accessory 25 amp fuse.
And with all the wiring confusion, could the alternator/regulator have been damaged and be the cause of the short? You might want to pull the alternator and have it checked just to be sure and start over with those wires.
Post Number 14 top photo shows a White plug going into the alternator, comes out of voltage regulator. It is what feeds the field winding to make the alternator make output out of the output terminal. Field terminal controls the charge rate from what the voltage regulator measures. Simon C
I replaced the wiring end connectors to the key switch to eliminate that being an issue. I can put a fuse in the fuse box but once I turned the key to the accessory mode or to the run position it will blow the fuse. I tried your idea, I used a jumper wire to supply power from the red wire that also goes into the key switch and it blew the fuse The battery indicator light in the instrument cluster is still working so it wouldn't be a blown bulb there. I have removed the accessory wire to the alternator and it didnt change anything, still blew a fuse. I removed all of the wires, including positive and negative from the alternator and still blew a fuse. The alternator wasnt working when I started this job so I know the issue was already present prior to the alternator installation. I unhooked the wire going to the cold start switch and cold start solenoid and still blew a fuse. I dont believe so. the terminal i was told to plug it into was the W terminal on the alternator which just reads the engine rpms. but even with the alternator completely disconnected, I am still shorting out. Thank you for yalls patience today with replying! I was doing many other things unfortunately today which pulled quite a bit of my time from the skid but I am checking everything yall suggest and ask. Thank you so much for everyone helping! Im still trying to figure out where the short is at. -Kat
Your D+ output terminal according to the schematic feeds a splice that feeds the Instrument Cluster and from the other leg of the splice feeds the R2 Resistor( 47 OHM ) then becomes wire 452 Yellow then 451 Yellow then 454 yellow going to 455 Yellow and a whole lot more. The only way you will find the short is to disconnect 600Brown from the instrument Cluster and see if the wire feeding it from the alternator, which you will disconnect and feed from an ATO Fuse will burn or not.( I take an ATO Fuse holder with the 2 wires sticking out and put alligator clips on both ends to be able to put power into and out of the fuse --- Add wire to the fuse holder wires to make them as long as you want ) If it doesn't blow the fuse, the problem is in the Instrument cluster. If it blows the fuse the power is going to ground on the other leg of the splice , which is a lot of wires and connections. After studying the schematic that is what I would try first. Problem is in harness somewhere. Any questions fire away. Simon C
You said others have worked on it, could that be the wrong key switch? It looks similar to a lawn tractor switch and that type switch will ground when turned off to kill the magneto type ignition system. Figuring out what has been tried by others makes things twice as difficult.
Just want to clarify, put an ato fuse holder into the brown wire between the the instrument cluster and the resistor and see if the fuse in the ato blows? If the ato fuse doesn't blow then the instrument cluster is bad, if it does blow then continue chasing the yellow wires to find the short? Wouldn't the fuse blow if the instrument cluster is still hooked to the circuit though even through the ato fuse (but would blow this fuse first)? or are you meaning just unhooking the wire from the cluster all together so the instrument cluster is not involved in this wire anymore and see if my accessory fuse still blows? Edit to add: I unplugged the X7 plug at the instrument cluster which had the brown wire going to it, turned the key to acc mode and tried installing a 25 amp fuse and it blew. So im thinking the short is somewhere else in the yellow side of that circuit and not the instrument cluster.
Im unsure, I have been told that the local equipment shop did it, the old shop mechanic here did it, and that they've sent it to a guy to be worked on and fixed up. So not sure who has done what or if they did anything they said they did. But I do know the previous mechanics were good with basic oil changes and sharpening reels on mowers but not in depth diagnostics or repairs or quality "repairs". Im half tempted to just get a whole new wiring harness for this thing.
Try a internet search for a tool called an ‘electric short finder’ that may aid with finding where the problem is. You might want to find what is causing the issue before choosing to buying a harness. Very discouraging to spend money and do the work only to have the same problem.
I made my own light bulb tster that i have plugged into the fuse that keeps blowing, to see what direction my short is going. So far i have traced it through the key switch, through the key switch fuse, and to the starter positive terminal and from there I have 4 directions to go. I have eliminated one direction so far and working on the others currently. Fingers crossed I can find where its shorting out. I really appreciate everyones help again! I have learned so much more on electrical diag these last few days
I was going to put the ATO Fuse power at the alternator end of the Brown Wire, with X7 end disconnected and yes if the fuse does still blow, problem is on the other legs of yellow wires somewhere. You could buy a new harness, only to find a wire shorting inside a light fixture and still blowing the fuse with the new harness. Better to find what is shorting to ground. Simon C
I am trying to find it just in case its not in the harness. my short isnt after the starter so i decided to start over from my test and found that i traced the wrong wire from the schematics. If i got from K4 relay on page 4-15 down to the junction and follow wire 451, it intersected at X13 connector. I unplugged that connector and my light turned off at the fuse, indicating no more short. But that connector has two yellow and white wires going into one side (one is my 451 wire) and then a black wire coming out the other side. The schematics are showing all 3 should be the same color. I followed that wire up and it intersected with about View attachment light.jpg
Now isolate the 2 yellow/white wires, by unplugging,(one at a time), the X1 and x99 connectors. Leaving the x13 together. That should tell you weather its between x1 and x13, or x99 and x13. You cant always trust electrical diagrams 100%
The easiest is to go to your Picture Schematic4-15 and on left side is Wire452. --- Hook the power at the disconnected alternatorr on the Brown 600 as I said. The power will arrive at 452 Yellow and if you follow the schematic goes many different directions. Disconnect 1 at a time and it will be clear which harness is grounding out. or you can do as Arny says above. Simon C
You’re doing awesome, just be aware that all those black wires are generally ground.
Also check to make sure all the harness connectors are attached to the correct components. Just because it fits doesn’t mean it’s correct.
That statement is very true and has caused some problems that people sent the machine to auction over not being able to figure out. Very good reminder. Simon C
Thank you everyone! I will continue tracing the short and follow up with yall next week! It has been a busy day at the shop today so I havnt gotten much done on the skid. I will update yall next week for sure though!
Have you had a look any more at your harness to see what was blowing your fuse test set up. Wondering if all is okay. Simon C
Good morning! Yes I think I have found it!! So we do not have a dual flasher switch like shown in this schematic. At plug x13, we have the two yel/wht wires 451 &453 going directly to a ground wire, Im assuming x12 connector into wire 124 after the dual flasher switch, by -passing what should be a switch and relay. I had traced everyone of those grounds in every direction and nothing removed the short. I talked to a retired mechanic at this electrical class i went to for our other equipment and he suggested unplugging the x13 plug and see what happens and what works/doesnt work cause it could be a short directly to the ground with that plug. The yel/wht wires do have power at them.
Sounds like you are on the right path. If a switch or relay has stuck contacts, it can be a little work to figure out also. Power can not go through a switch and only go to ground without powering up a bulb or light. Otherwise instant fuse gone or breaker popped. Simon C
Got the wiring put back together. She is charging over 14V and everything is functioning properly on it! My boss doesnt know when the last time was that he didnt see the battery light illuminated on it. Thank you so much for your help and especially for following up!
52 posts later and Hip-Hip Horray. Congratulations. You are on your way to becoming a schematic guru. Simon C
I really enjoyed learning the schematics better and understanding the electrical more! Thank you so much for all of your help! You are the best!
Been an interesting thread to follow, Congratulations on the win!
You lost me, what was the problem?
Never mind, I see it. Congrats
Im currently having the same issue. John Deere 260 I purchased got machine running with a rebuilt injection pump. Alternator is not charging they had no wires connected to D+ all other wires look correct per schematic. I ran the machine with the alternator not charging and my controls all worked. shut off the machine and recranked and started to blow 25amp fuse and controls will not unlock. If I unplug the 2 yellow and white wires from the black plug I do not blow the 25amp fuse, as soon as I plug it back in I blow the fuse. Would you mind explaining to me in simple terms how you fixed your problem before I pull out whats left of my hair. Thank you
Post a picture of your wires and cables at alternator for a better response from those of us who are not there to maybe be able to suggest something. Simon C
This is how it was wired when I got the machine and was not blowing the 25a acc. Fuse . I was able to run it for about 30min. Bucket worked fine then started blowing fuse and controls are locked
Your post #60 looks okay from what I see. Go to post #6 at page#1 by Diesel Dave , and you will see that the ACC-25 Amp fuse on picture number 1 Feeds #445 Yellow Wire. Now go to page number 3 of the schematics and Wire Number 445 Feeds K4 Relay Pin Number 30. Power leaves there by pin #87 to go to splice and wire 451- Yellow/White to X13 plug. Power also leaves the same Pin # 87 to go to Wire 454 Yellow to go to X11 plug to 455Yellow and on to Picture #4 Back-up Alarm Fuse. These wires will have to be checked for grounding out. You could disconnect one of the plug-ins at a time to see if the fuse still blows. The person with the original post K Stewart had the same problem and finally found it by tracing wires. It can be done. Simon C