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Discussion Starter · #1 ·
Getting frustrated. 2003 JD790.

It started fine and I drove it to the front gate. Shut it down to open. When I got back on, it would not crank.

First thought, Battery and/or cables, connections, etc.

Battery tests as Ok and fully charged. Even tried another known good battery, still no crank over.

Had a problem with the cables 8 months back. Replaced with new, but I re-cleaned terminals and cables and cleaned/remounted ground cable and yet still no cranking.

The lights work fine and the Instrument panel light and gauges work. I hear a relay when I turn the key to crank and the warning lights dim a bit, but it’s like the starter is frozen.

I tested the seat safety switch and it tested as Ok plus I tried jumpering it as well, still no cranking.

Pulled the instrument panel apart a bit to test components there as well.

I printed the Factory Service Manual procedures for troubleshooting the cranking system. Not the clearest or easiest instructions to follow...

I know I need to test the other three safety switches (PTO, Neutral Switch, e, assorted relays and starter switch. Beyond that, guess I would need to test the Starter/Solenoid unit.

Any tips or advice on how best to proceed?

The tractor is stuck in my front yard with a heavy box blade and I need to get this thing going.

Thank You.
 

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You made sure all your safeties were in the right position? Neutral starting position, seat switch PTO? Check the starter fuse relay? I had the main fuse go out on my 4520. Nothing would turn over. Changed the fuse and all is well ok mine.
 

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I had a 790 and can't recall the electrical. Some of these tractors have a Fister module that control the switch to the fuel injector...on that arrangement they will crank but you can't switch open the fuel injector pump....the 790 may be mechanical on the shut down....you can take a battery pack and or jumper and switch the solenoid in to see it if will start...this is independant of the key switch. you could also pull it for starting....
 

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Discussion Starter · #4 ·
Thank You for the replies. All of the Safety Switch items are in the correct positions to allow for a start. That was the first thing I checked. Of course, it could be a bad switch or wiring/connection.

I tested the fusible link and it looks and tests to be Ok.

As I said, the starter will not turn over. According to the manual, there is a fuel relay switch.

Am still checking everything.
 

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Discussion Starter · #5 ·
Finally, found the problem. The battery cables and terminals, ground connection were all due some attention and I found a couple broken wires on the flasher relay that needed mending....

But what it turned out to be, was the Connector for the PTO Safety Shut Off Switch.

While tracing out the wires and switches I had the ignition switch in the On position. When I wiggled the connector for the PTO Safety Switch I heard a click or two under the instrument panel.

Sure enough, the connector was partially loose. The plastic catch on the connector was broken.

Now it is clean and I used a plastic wire-tie to cinch it together.

Thank You for the replies.

DC
 
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