JD 770 electrical starting issue

newtron · Mar 29, 2017

so I've looked thru the forum trying to solve this problem but I'm at a loss.

So I was driving the tractor, shut it down, and then it would not start again. I turn the key and there is nothing, no power, lights, anything.

I have tested voltage at battery and at the starter and get 12.4. I can get 12 volts all the way to the ignition switch. Then I turn the key and get nothing. I've pulled the panel apart and have got the ignition switch out. There are 5 wires to the ignition switch, . 1 wire is is 12v supplying power to the ignition switch and it has its own clip, then there are 4 wires that come off the back into a separate clip. The strangest thing is if I disconnect the the 4 wires from their clip (leaving the 12v supply connected) and I turn the key I get 12volts across, and If I turn it to "crank" I also get 12v across.

As soon as I reconnect the 4 wires back into the tractor and I turn the to "on" there is no voltage anywhere. There is non at the 12v source to ignition or any of the other wires. Where do I go from here? also how is an ignition switch grounded? and could insufficient ground cause all this even though I'm getting proper voltage?

Thanks

joecdeere · Mar 29, 2017

I have a PDF of the Tech manual you're welcome to, all the wiring is in it.
Shoot me your email if wanted

Joe

amaxwell · Mar 29, 2017

newtron said:
so I've looked thru the forum trying to solve this problem but I'm at a loss.

So I was driving the tractor, shut it down, and then it would not start again. I turn the key and there is nothing, no power, lights, anything.

I have tested voltage at battery and at the starter and get 12.4. I can get 12 volts all the way to the ignition switch. Then I turn the key and get nothing. I've pulled the panel apart and have got the ignition switch out. There are 5 wires to the ignition switch, . 1 wire is is 12v supplying power to the ignition switch and it has its own clip, then there are 4 wires that come off the back into a separate clip. The strangest thing is if I disconnect the the 4 wires from their clip (leaving the 12v supply connected) and I turn the key I get 12volts across, and If I turn it to "crank" I also get 12v across.

As soon as I reconnect the 4 wires back into the tractor and I turn the to "on" there is no voltage anywhere. There is non at the 12v source to ignition or any of the other wires. Where do I go from here? also how is an ignition switch grounded? and could insufficient ground cause all this even though I'm getting proper voltage?

Thanks

Could it be something as simple as a safety switch, (pto on ,clutch safety switch ) ?