JD L120 Wont Run Unless Bypass Solenoid

J

JonnyBlaze

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Ive read up on this and I know its either ignition switch, pto switch, rio switch, solenoid or brake switch. I ordered a new solenoid and ignition switch. Brake switch is still intact at the mount.

New battery. Runs great if I jump the solenoid. They ignition switch does weird things depending on position its in while its running. If I have it in one position and press the reverse pedal, the mower deck starts moving then it stalls. Also, pto switch only turns on the deck when in a different key position.

Headlights dont work at all.

Fuse near solenoid is good. No power to starter side of solenoid. No power to purple wire on solenoid. No power coming out other end of fuse.

Also found a stray black wire. Not sure where it goes. Says P.E.D on the connector.
 

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J

JonnyBlaze

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I figured it out! That black wire is supposed to be grounded! Grounded it and it fixed all my problems!
 
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JonnyBlaze

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Except for the headlights. They still don't work. Bulbs are good.
 
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bertsmobile1

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Firstly the problem is not in the solenoid.
The only thing the solenoid does is to turn the power to the starter motor on & off the rest of the time it just sits there going rusty.
If the fuse is blown then the ignition switch gets no power FROM THE BATTERY thus it can not trip the solenoid to start the engine.
When running the ALTERNATOR puts power into the ignition switch thus things that won't work when the engine is not running suddenly start to work.
If there is no power from the fuse then the fuse is bad or the fuse housing is bad.
I don't know what you have read, but what you should have been reading was the JD Technical manual then you would not have just bought a $ 30 solenoid that you did not need to replace. ( 1/2 the cost of the manual )
From the solenoid hot terminal a wire runs through the fuse then to the B ( battery ) terminal on the ignition switch.
From there it goes to the S ( Start ) terminal & to the A ( alternator ) terminal & to the PTO switch.
If there is no electricity coming in then there can be no electricity going out.

Starting circuit is totally independent of the running circuit and the PTO circuit

STARTING
Fuse to B
B to S
S to PTO
PTO to Brake
Brake to Solenoid

There are diodes all over the place on a JD so God only knows haw the circuits work when you are back powering them through the alternator.
 
J

JonnyBlaze

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bertsmobile1 said:
Firstly the problem is not in the solenoid.
The only thing the solenoid does is to turn the power to the starter motor on & off the rest of the time it just sits there going rusty.
If the fuse is blown then the ignition switch gets no power FROM THE BATTERY thus it can not trip the solenoid to start the engine.
When running the ALTERNATOR puts power into the ignition switch thus things that won't work when the engine is not running suddenly start to work.
If there is no power from the fuse then the fuse is bad or the fuse housing is bad.
I don't know what you have read, but what you should have been reading was the JD Technical manual then you would not have just bought a $ 30 solenoid that you did not need to replace. ( 1/2 the cost of the manual )
From the solenoid hot terminal a wire runs through the fuse then to the B ( battery ) terminal on the ignition switch.
From there it goes to the S ( Start ) terminal & to the A ( alternator ) terminal & to the PTO switch.
If there is no electricity coming in then there can be no electricity going out.

Starting circuit is totally independent of the running circuit and the PTO circuit

STARTING
Fuse to B
B to S
S to PTO
PTO to Brake
Brake to Solenoid

There are diodes all over the place on a JD so God only knows haw the circuits work when you are back powering them through the alternator.
Click to expand...

Thanks for the reply. Like I said above, I figured it out. Found a ground that wasn't hooked up. New solenoid was only $12.00. I'm sure I will have a use for it sometime in the near future.
 
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