# New Holland 1720 Blows Fuse



## Old Blue Tractor (Mar 11, 2019)

Hi All, I'm new to the forum and would be extremely grateful to get an answer to this problem with my 1996 1720. The tractor has been running fine. Today In started the tractor and left it idling for approximately 10 minutes and then shut it off. I returned another 10 minutes later and tried to start the tractor. I was demonstrating the starting procedure to a potential user, so I rotated the key backwards to the warm up position and nothing happened. No dash lights, dead. Same when I turned the key forward.
I discovered that the 30 amp fuse on the hot wire from the starter to the key was blown. I replaced the fuse and when I rotate the key backwards it blows. I did this twice with the same result.
Right before the fuse breaks I think I hear a little click in the engine compartment, near the front of the motor.

Does anyone out there have an idea? Thanks

Wade


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## thepumpguysc (Jan 25, 2015)

Glow Plug relay.?? Inj. pump solenoid.?? Just throwin them out there..


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## Old Blue Tractor (Mar 11, 2019)

Thanks Pump Guy. I guess I need to get a manual. Where is the Glow Plug relay located? and is there a way to test it?


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## pogobill (Jan 31, 2012)

Sounds like a short in the wiring to your glow plug relay or the wires to the glow plugs. Trace the wires from the glow plugs back and see if there is a problem with the wiring.


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## Old Blue Tractor (Mar 11, 2019)

pogobill said:


> Sounds like a short in the wiring to your glow plug relay or the wires to the glow plugs. Trace the wires from the glow plugs back and see if there is a problem with the wiring.


Thanks for the help. I see one wire that goes from the starter solenoid to the glow plugs. It looks clean. I'll keepooking.


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## pogobill (Jan 31, 2012)

Does the fuse blow when the key is turned towards the start position?


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## RC Wells (Dec 26, 2008)

There is a diode located between the alternator and the starter that prevents the starter from back feeding the alternator. It looks like this: https://partstore.agriculture.newholland.com/us/parts-search.html#epc::mr49096ar425917731

When it fails the fuse will blow, and you hear the alternator fields momentarily engage just as the fuse blows.


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## Old Blue Tractor (Mar 11, 2019)

No. The fuse only goes when the key is rotated counter clockwise. When the key is rotated clockwise the starter engages and the engine turns over.


pogobill said:


> Does the fuse blow when the key is turned towards the start position?


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## Old Blue Tractor (Mar 11, 2019)

Would the diode be the issue if the fuse only goes when the key is rotated counter clockwise?

Yesterday I rigged a hot wire from the battery to the glow plug "manifold", heated the glow plugs for 20 seconds or so and it fired right up. Without being able to supply power to the glow plug relay because the fuse goes, how do I test the relay? I have traced all the wires and don't see a short. Would this happen if a glow plug is bad? And, do I need to have power to the glow plugs in order to test them? Thanks for all your help and patience.


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## maxreco (Sep 30, 2015)

Hi Old Blue, I'm having a similar issue on my 1620, and before I order the diode (for $70!!) I wanted to ask you if you found a solution to your problem. It sounds quite familiar to mine.


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