I have a JD D170 and the 20amp fuse coming off of the battery blows when the PTO switch is pulled. It had blown a few weeks ago and after replacing it, the mower worked fine for a while. Recently, it blew and killed the mower while in 'mid mow'. Now it blows shortly after trying to engage the blades (pulling the PTO switch). I have tracked wires all over and can't find a short of any kind. Any suggestions and advice is GREATLY appreciated? TIA
John Deere D170 blown fuse troubleshooting
- Thread starter farriscl
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NorthBama
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https://xtremeope.com/?mrkgcl=1182&...LtJlPXXN2dgMSWZR1-X9B00e9mMHJwlcaAu7iEALw_wcB
some good videos here at this site that may be helpful troubleshooting a bad PTO clutch
some good videos here at this site that may be helpful troubleshooting a bad PTO clutch
It's worth taking a couple measurements to see if you can determine if the clutch itself is perhaps 'going' bad or not(I'm defining as windings inside PTO shorting and drawing higher than normal current due to lower than normal resistance, which btw is not a high probability). The clutch resistance should be in the neighborhood of 2 to 4 ohms. That corresponds to a normal current draw of 3-6 amps. Search this site as there are several threads about PTO's blowing fuses. Search my name and I've been posting to another thread about the same subject. I attached a guide I found online if you want to know more about these clutches. I realize it can be difficult to track down an intermittent short but that's exactly what you are looking for. It would also be nice to know how much current is being drawn through that 20a fuse during "normal" operation with the PTO on. With headlights off, it should be under 10a which is within the typical range of a lot of meters.
Another technique to try and nail it down to a defective PTO is to disconnect it at the clutch, wire the clutch directly to the battery, with a fuse in line of course, and a switch and see if while using it, the 'hotwired' PTO fuse blows at any point. If it does, then you know it's the PTO and the intermittent short is from the coil inside or the wiring to the 'hotwired' connection. If the existing fuse blows again, then you know the short is elsewhere keeping in mind that the ignition key in the run without lights position connects the B L and A1 terminals together, and any wire connected to those is "hot" with 12vdc and shorting anywhere will pop the 20a fuse.
Having a wiring diagram is most helpful. I think the Tech Manual for this machine is TM113219. Unfortunately I don't think it's readily available for a free download. If you intend on keeping the machine for a while, it's a great investment!
Keep us posted...
Another technique to try and nail it down to a defective PTO is to disconnect it at the clutch, wire the clutch directly to the battery, with a fuse in line of course, and a switch and see if while using it, the 'hotwired' PTO fuse blows at any point. If it does, then you know it's the PTO and the intermittent short is from the coil inside or the wiring to the 'hotwired' connection. If the existing fuse blows again, then you know the short is elsewhere keeping in mind that the ignition key in the run without lights position connects the B L and A1 terminals together, and any wire connected to those is "hot" with 12vdc and shorting anywhere will pop the 20a fuse.
Having a wiring diagram is most helpful. I think the Tech Manual for this machine is TM113219. Unfortunately I don't think it's readily available for a free download. If you intend on keeping the machine for a while, it's a great investment!
Keep us posted...
mechanic mark
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https://www.google.com/search?q=how...5i39j69i59.27700j0j4&sourceid=chrome&ie=UTF-8
check air gap at PTO clutch 3 places with feeler gauge
https://www.google.com/search?q=ogu...e..69i57j0.42343j0j9&sourceid=chrome&ie=UTF-8
check air gap at PTO clutch 3 places with feeler gauge
https://www.google.com/search?q=ogu...e..69i57j0.42343j0j9&sourceid=chrome&ie=UTF-8
bertsmobile1
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Take Telesis's advice and buy the manual.
It is not cheap in either price nor quality and will,pay for itself the first time you use it.
When diagnosing these type of problems I use patch leads ( Jumpers with spades on them ) to make the same connections as the PTO switch would at the PTO switch plug.
If the problem goes away it is the switch which can go bad or get full of things ( like ants ) that short out the PTO power to one of the ground contacts.
It is not cheap in either price nor quality and will,pay for itself the first time you use it.
When diagnosing these type of problems I use patch leads ( Jumpers with spades on them ) to make the same connections as the PTO switch would at the PTO switch plug.
If the problem goes away it is the switch which can go bad or get full of things ( like ants ) that short out the PTO power to one of the ground contacts.