# JD LT155 Won't crank over



## Jimbotron

Hello from a Newbie to the forum!
I inherited a John Deere LT155 that won't crank over, it has a new battery, ignition switch and starter solenoid but still won't crank over, if I jump the solenoid it will crank and start but then I can't shut it off, I have to pull the spark plug wire off!
Any suggestions???


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## sixbales

Howdy Jimbotron, welcome to the tractor forum.

Attached are wiring diagrams for a JD LT155, one for a 3 amp system (3 position keyswitch) and one for a 20 amp system (4 position keyswitch).

For the 3 amp system the keyswitch positions are: 1) Off, 2) Run, 3) Start/crank. For the 20 amp system the keyswitch positions are: 1) Off, 2) Run w/lights, 3) Run w/o lights, 4) Start/crank.
















Do you have power to the keyswitch? If not, there is a fusible link between the battery and the keyswitch. You can blow this fusible link in a heartbeat if power is shorted accidentally. Also check all fuses.

There is a white wire that goes to the ignition module. The white wire needs to be grounded in order to kill spark to the engine. When the key is turned off, the white wire should be grounded, and since it keeps running, obviously the white wire is not grounded when the switch is turned "off".

Your problems could be related to a faulty safety switch. The seat switch is often the culprit....disconnect and use a jumper wire to bypass it and check results. 

There are guys on this forum that are much more knowledgeable than me. Hopefully, someone will pick up on this and carry on.


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## Jimbotron

sixbales said:


> Howdy Jimbotron, welcome to the tractor forum.
> 
> Attached are wiring diagrams for a JD LT155, one for a 3 amp system (3 position keyswitch) and one for a 20 amp system (4 position keyswitch).
> 
> For the 3 amp system the keyswitch positions are: 1) Off, 2) Run, 3) Start/crank. For the 20 amp system the keyswitch positions are: 1) Off, 2) Run w/lights, 3) Run w/o lights, 4) Start/crank.
> View attachment 36252
> View attachment 36253
> 
> 
> Do you have power to the keyswitch? If not, there is a fusible link between the battery and the keyswitch. You can blow this fusible link in a heartbeat if power is shorted accidentally.
> 
> There is a white wire that goes to the ignition module. The white wire needs to be grounded in order to kill spark to the engine.
> 
> Your problems could be related to a faulty safety switch.
> 
> There are guys on this forum that are much more knowledgeable than me. Hopefully, someone will pick up on this and carry on.





sixbales said:


> Howdy Jimbotron, welcome to the tractor forum.
> 
> Attached are wiring diagrams for a JD LT155, one for a 3 amp system (3 position keyswitch) and one for a 20 amp system (4 position keyswitch).
> 
> For the 3 amp system the keyswitch positions are: 1) Off, 2) Run, 3) Start/crank. For the 20 amp system the keyswitch positions are: 1) Off, 2) Run w/lights, 3) Run w/o lights, 4) Start/crank.
> View attachment 36252
> View attachment 36253
> 
> 
> Do you have power to the keyswitch? If not, there is a fusible link between the battery and the keyswitch. You can blow this fusible link in a heartbeat if power is shorted accidentally.
> 
> There is a white wire that goes to the ignition module. The white wire needs to be grounded in order to kill spark to the engine.
> 
> Your problems could be related to a faulty safety switch.
> 
> There are guys on this forum that are much more knowledgeable than me. Hopefully, someone will pick up on this and carry on.




Thanks Sixbales, I have a starting point and with the wiring diagram I will start tracing this thing down, any other suggestions are certainly appreciated!!


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## Jimbotron

Jimbotron said:


> Thanks Sixbales, I have a starting point and with the wiring diagram I will start tracing this thing down, any other suggestions are certainly appreciated!!


Thanks Sixbales, for the headsup about the white wire, all the safety switches worked correctly, however they were not completing the circuit and being grounded, once grounded everything works as designed, thanks again for your help!


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