# 790 wont start?



## Diamond (Dec 17, 2011)

I have a 790 and it wont turn over no lights nothing! I have 12volts at the starter and at the back on the key switch. Ive been trying to trace it all over but i cant find the problem. Is there a way to jump some wires to eliminate the key switch, starter, and there is a black finned thing that has wires on the fuel tank inside the engine compartment. Any help would be great thanks


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## Hoodoo Valley (Nov 14, 2006)

Does it have the original John Deere "Strong Box" battery in it? They are noted for just up and going bad with dead battery type symptoms.


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## Thomas (Nov 1, 2006)

Have you check all safety swtichs.


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## Mickey (Aug 14, 2010)

Not familiar with your rig. Can you clarify your comment on having 12V at the starter? Does this starter have the starter solenoid attached to the starter and there is power to the solenoid or is the power available directly to the starter itself?


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## Diamond (Dec 17, 2011)

I do not have the original battery. the battery positve cable goes to the starter and has constant 12v. the solenoid and starter are one unit. It does have 12v to the starter and a smaller white wire to the solenoid. I get power out of the switch when i turn it to either the start,run or glow plug position. I will check the safety switches but even if they are bad would i not still have turn signals or flashers? Thanks for the responces and anymore info would be great because im running out of things to check. David


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## Thomas (Nov 1, 2006)

By chance pto engage?


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## Mickey (Aug 14, 2010)

One does need to try and be as tech accurate as you can when writing and asking for help. As you state the sol is mounted to the starter, I'm betting the batt cable is going to the sol and not the starter. What happens when you bridge across the 2 larger cable connections on the sol? When you go to engage the starter via the key, do you see any voltage to the small wire going to the sol?

Briging across the 2 large connection, the starter should engage. If not there is a starter issue. If you see battery level voltage to the small wire connected to the sol, most likely a sol problem. If no voltage present at the smaller wire at the sold end, problem is most likely the ign switch or some safety switch.


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## ErnieS (Jun 1, 2011)

Diamond said:


> I do not have the original battery. the battery positve cable goes to the starter and has constant 12v. the solenoid and starter are one unit. It does have 12v to the starter and a smaller white wire to the solenoid. I get power out of the switch when i turn it to either the start,run or glow plug position. I will check the safety switches but even if they are bad would i not still have turn signals or flashers? Thanks for the responces and anymore info would be great because im running out of things to check. David


Do you have 12 volts from the starter lug to a ground on the engine both at rest and when you try to bump the starter? If the starter was bad, you still should have glow plugs, signals, etc Check the ground cable to the battery. It may be good enough for your meter, but not for much else when you turn on the switch.


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## firedog5 (Jan 1, 2012)

*Having the same problem*

I went to start my 790 yesterday and it clicked, then no lights, gauges, or starter. Replaced the battery and cleaned the terminals, checked all the interlock switches and ignition switch and found no problem. After looking at the schematic it started looking like a bad ground so I pulled the battery ground cable and the end that attaches to the frame had a lot of rust as well as the pan part of the frame it attaches too. Cleaned everything up and it starts great.


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## Diamond (Dec 17, 2011)

Mickey The small white on the starter does not have any power to it at anytime. the the ign switch has power coming out at all the key positions. the fuse box has power to every wire except a red and black one have not been able to trace it yet. ErnieS and Firedog5 i will check the ground side cable but when i check for volts my ground lead from my meter is to the floor pan so I think the ground should be good but I will check. Thanks guys for your help! Will post back what I find. David


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## Byronc (Sep 18, 2016)

Same issue here. 790 JD ran for 30 min, turned off for 10 min. Got back on to start the tractor turned key got about 1-2 seconds of starter and then nothing. Turn key now and it's dead. No lights no clicking, no dash lights, nothing but silence. Where do I start? I did look at the fuses in the box on the left side of the tractor unde the panel, all are good.I am going to borrow a meter tomorrow. Where do I check? Thank you all for any hel you can provide.


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