4720 keeps blowing ignition fuse

[AKfish]

By starter solenoid are you referring to the fuel shutoff solenoid? If there's a starter solenoid it must be built into the Bosch-made starter which may explain why it's not listed on the JD parts list...

But I can still test the starter motor by disconnecting it and see if the fuse still blows, can I? I doubt the starter would be at fault by who knows.

The engine starter has a solenoid, too. jd110 and jenkinsph are both saying the same things - more or less.

Troubleshoot by process of elimination. If you disconnect the starter and then engage the ignition key and the fuse blows - the problem is upstream of the starter. Seat safety lockout, etc. That was jenkinsph point.

jd110 suggested to work the problem in a similar manner. Eliminate the seat as the problem, eliminate the park brake as a problem, etc.

I think you've already "put your butt on the problem". Cranking the air seat down.... it might have gone down too far!

Keep us posted.

AKfish

 

[Karl2]

The engine starter has a solenoid, too. jd110 and jenkinsph are both saying the same things - more or less.

Yes I realize the starter has a solenoid but on this model of starter it is either not exposed or very well camouflaged. Speaking of which, in the New Holland forum I found someone who has the same problem with his late-model TN65 and is able to bypass-start and operate it. However even though he also has a Bosch starter his has the solenoid in plain sight. That said, I don't intend to attempt bypass-starting my tractor anymore. If I need to I will test for starter malfunction by simply disconnecting it and see if the fuse still blows when I turn the key to the start position. However I suspect the problem is upstream so I'll troubleshoot there first.

Troubleshoot by process of elimination.

It finally stopped raining so I'm getting back to it. The first procedure I intend to do is to visually inspect wires under dash panels for obvious damage, could save me a few fuses as I'm running low on them and need to resupply.

Next I will test all NSS switches I can think of starting with the seat switch. Since I don't have a service manual yet I may miss some but common sense should help. If I were an ignition I would look for these before allowing the starter to crank:

-PTO switch: must be off.
Human testing action required: bypass PTO switch and see if fuse still blows. Not too sure how to do that yet but info about how to bypass a three-pronged switch must be available on the Net somewhere.

-Hydro pedals: must not be jammed in travel position.
Human testing action required: 1) make sure pedals and sensors are not jammed and see if fuse still blows. 2) find and bypass switch, proceed as with the other NSS switches

-Seat switch: no check required for starting (hydro tranny) but must be depressed to maintain ignition when rear PTO is on.
Remark: even though the seat switch position is normally not relevant to the starting sequence on this tractor model, it is possible that a malfunction in said switch could be causing the fuse to blow
Human testing action required: test switch using bypass procedure.

Note: I suppose it is possible that the next two items' safety feature is controlled by the PTO NSS switch rather than their own.

-Park brake: no check required for starting (hydro tranny) but must be engaged to maintain ignition when rear PTO is on and seat switch not depressed.
Human testing action required: find and test switch (if present) using bypass procedure if feasible.

-Transmission position lever: no check required for starting (hydro tranny) but must be set on neutral to maintain ignition when rear PTO is on and seat switch not depressed.
Human testing action required: find and test switch (if present) using bypass procedure if feasible.

I don't know if other controls have NSS switches but I think the above are the primary suspects. Does this make sense?

 

[Karl2]

Hot dang it starts!

Bypassing the seat switch shut off the PTO indicators and the tractor started right away without blowing the ignition fuse

BUT

as soon as the engine cranked I heard another fuse pop. This time it's the F11, a 20A fuse labeled "Air Seat/Diverter Option", and an ominous hot circuit aroma wafted up prompting me to cut the engine at once

I think I know the source of this problem. I used a tiny computer-grade alligator wire to short the female connector behind the seat that connects to the cable leading to the seat switch. I suspect this wire has too much resistance for the circuit causing it to overheat and pop the fuse. Is there a preferred method and proper wire to bypass the seat switch without risking anything catching fire while driving the tractor back up the driveway?

I don't have any spare fuses above 15A but I think I can do without seat control and diverter for the 600-foot drive. I'm a little puzzled as to why the seat compressor and diverter circuit would be affected by the seat switch but obviously it is in some way.

 

[AKfish]

Congrats!! You're darn near home.. er, back up the driveway! Don't know how the air seat ties into the safety presence switch but it sounds like they have a shared circuit.

Is your dealer any help on this? Call from your cell and have the tech walk you thru a workaround on the seat switch..? I think I'd call 'em anyway and let them know of the problem and see if they might have any info from Deere regarding this issue. Your tractor might not be the ONLY one to have this happen!

AKfish

 

[Karl2]

Congrats!! You're darn near home.. er, back up the driveway! Don't know how the air seat ties into the safety presence switch but it sounds like they have a shared circuit.

I fashioned a jumper from a piece of 12 gauge solid copper wire to replace the alligator wire and that did the trick, no more fried wire smell in the cab and engine starts like a champ so I was finally able to bring the tractor back to the house and driveway is back in business.

I was not at ease having to leave the tractor practically on the side of a main road in plain view of passing motorists . We couldn't see it from the house and I've read threads on this forum about bozos tampering with or even attempting to steal stranded tractors while they were out of view from their owners.

So most of the ordeal is over but the F11 fuse still keeps popping so I can't use the diverter valve or adjust my seat. Not a big deal since I only use the diverter valve to operate the rear snowblower chute with the SCV in winter. As for the seat however it is completely "deflated" at the moment and while that's fine driving at 2 mph on a smooth surface I can't imagine myself not doing anything about it very soon.

Is your dealer any help on this?

Not really, but I can't blame him. I purchased this tractor used through our local Massey-Ferguson/Kioti dealership (MF has always been very popular with farmers and snow removal operators in these parts), he cannot offer official support for other brands but will usually fix most makes. It's expensive though. The nearest JD dealership is three hours away and will send a tech if I really insist, but ignores my orders for parts. There's a closer -and much nicer- JD dealership across the border in Quebec but they are not authorized to send techs to Maine. I do however purchase most of my JD parts from them in person, there is no Customs duty on parts because I have a commercial business license to prove I need them for work purposes. Most JD owners in the area do the same.

Your tractor might not be the ONLY one to have this happen!

If you're talking about the seat compressor/diverter issue, I wouldn't bet on that just yet

As for the starting failure/PTO indicators lit problem then no, I'm not the only one who had to deal with this. From what I could gather on the Net it does happen to many tractor owners, but the causes are varied and usually spread among various NSS failures. On hydro tractors both the seat switch and PTO switch are cited very often.

As for the reason behind the F11 popping fuse my current tentative theory is that perhaps there's a system that faults when the seat switch wire is shorted, as a deterrent to those tempted to permanently bypass the switch. I believe that replacing the faulty switch should solve this problem. I guess a trip to Quebec is in order for later this week!

 

[jenkinsph]

Karl,
Glad you got it figured out but keep us informed as to how this finally plays out. I would like to know of any other quirks you run into.



Steve

 

[ddivinia]

Is your tractor still under warranty?

D.

 

[Karl2]

I would like to know of any other quirks you run into.

Well! I am about to give the tractor a thorough checkup as it's creeping up towards the 1,000-hour mark (986 at the moment) so I'm likely to run into a few trouble spots. This morning I completely removed all dash panels (had to remove steering wheel as well) and looking at the wiring I noticed some wires had been taped. It doesn't look like a pro job so I suspect former owner did a few mods that may be interfering with proper operation of the electrical system. The dealer had showed me a picture of the tractor shortly before he sent someone to pick it up upstate and I had noticed that 4 extra work lights and a large three-beacon rack had been installed on the cab but these had been removed prior to delivery. Such equipment requires some fiddling with wiring and it may not have been done properly.

When I saw this I decided a complete check-up was in order to see if further owner mods have been performed. I would also like to get rid of the Error 8 error message (throttle sensor) which has been there ever since I got the tractor. This is an extremely common issue apparently and while it does not interfere with operating the tractor, it disables the anti-stall feature, and since I paid 30K for this used machine I would appreciate it if all features worked.

Ideally I would also like to fix the fuel gauge but that's probably hopeless unless I replace the whole instrument cluster/computer, and I am told the fuel gauge on a new cluster is likely to fail as well.

 

[ddivinia]

Well! I am about to give the tractor a thorough checkup as it's creeping up towards the 1,000-hour mark (986 at the moment) so I'm likely to run into a few trouble spots. This morning I completely removed all dash panels (had to remove steering wheel as well) and looking at the wiring I noticed some wires had been taped. It doesn't look like a pro job so I suspect former owner did a few mods that may be interfering with proper operation of the electrical system. The dealer had showed me a picture of the tractor shortly before he sent someone to pick it up upstate and I had noticed that 4 extra work lights and a large three-beacon rack had been installed on the cab but these had been removed prior to delivery. Such equipment requires some fiddling with wiring and it may not have been done properly.

When I saw this I decided a complete check-up was in order to see if further owner mods have been performed. I would also like to get rid of the Error 8 error message (throttle sensor) which has been there ever since I got the tractor. This is an extremely common issue apparently and while it does not interfere with operating the tractor, it disables the anti-stall feature, and since I paid 30K for this used machine I would appreciate it if all features worked.

Ideally I would also like to fix the fuel gauge but that's probably hopeless unless I replace the whole instrument cluster/computer, and I am told the fuel gauge on a new cluster is likely to fail as well.

Do you have the service manual? The troubleshooting section is rather good.

I had to replace my cluster, but it was under warranty.

I have not heard of the fuel gauge going out.

How old is it? Maybe it is still under warranty? The new ones have a longer warranty. Used to be 2 yr 2K hours, now it is 3 year 2K hour.

D.

 

[Karl2]

Is your tractor still under warranty?

Unfortunately not even though it's less than 3 years old. I bought it used and the warranty is not transferable.

It's not a major issue for me though. I consider troubleshooting and fixing the tractor myself as a hobby ever since I discovered that tractors are designed to be self-maintenance friendly and that major failures due to defective parts are quite rare in first-tier brands especially on diesel models. Many people don't realize there are resources available that can make them quite proficient at fixing their own machine provided they like doing such work and spend a lot of time operating their tractor. This is imperative if one is to acquire a "feel" of what the machine does and how it does it, and greatly facilitates troubleshooting.

Something that also helps me is the fact that even though this tractor will log at least 600 hours per year most of these occur during winter leaving me with plenty of time to learn my way through the machine's maintenance during spring and fall when working outdoors is most pleasant. That's how I learned how to maintain and fix my 1970 LeMans myself, as well as my motorcyles both of which I completely rebuilt two years ago, including engines. After I'm done with the tractor I'm restoring a vintage 1974 Honda CT70, the legendary small trail bike, to mint condition. I got one when I was 12 and never looked at a moped again. This one will be a gift for my daughter who'll be turning 13 in August, to replace her wimpish scooter. When she sees pictures of me long ago with that bike she says she wished Honda still made them. Well Daddy will "make" one. Parts were hard to find and often expensive but I got all the ones I need for the project.

I can't find my way through my F150 or my wife's Toyota Sienna though, modern vehicles may as well be from Mars as far as I'm concerned. It's not because I'm particularly old (I'm 45) but today's cars have what I call "turboloid molecular engines" meaning they don't make a whole lot of sense to me, and I am a computer programmer by trade!

Compared with that the tractor is a hobbyist mechanic's dream.