Safety interlocks - not just the seat switch.... check the entire circuitry...

Not familiar! Will the blades engage normally, if the reverse override switch is held in? In other words, if you held the override in, could you mow going forward?

I'm thinking, there is a switch which detects whether you are going normal (anything but reverse) or reverse. While it works properly in reverse, it's messing up when not activated to go into reverse.

After a little more thought, I'd guess the "reverse override switch" parallels the switch you might be looking for. The switch is probably normally closed until you go to reverse, at which time it opens. Then the pushing of the override switch, jumpers around the normally closed switch, which was thrown open by going to reverse.

Send me an email and I can help IF you have a BIG mailbox.

Turn the seat around. Tape the RIO down and there you go. Upside is you get a better view of where you are going....backwards.

I found the link to download the manual. (You won't need a big mailbox)
I can't post it here without getting banned, so email me if you want it.
It has schematics and trouble shooting procedures.

I'd check the ground wire for the PTO clutch at its tractor harness connector, a poor crimp or broken wire at the connector can cause these symptoms.

Did anyone figure out this problem? I have the exact same issue...please advise.

What did you have to do to solve this issue? My JD l120 has the same issues. I was cutting away and it stopped dead in it's tracks. The blades engage when I get off the seat and when in reverse holding the RIO button down. I would appreciate some help on this one. Thanks.

I ripped out all unnecessary wiring and switches of mine long ago. All that's needed is the engine wires, the headlights, hour meter and the electric clutch. And I put a reverse light circuit in using the convenient reverse cutout switch.

Nothing sucks more when you need to get the yard cut but gotta fiddle around with some 3rd rate wiring dictated by corporate lawyers and government regulators.

I am not a professional. I just figured it out on my own which wires do what. You can too.

I also fixed my loose steering by building up welds on all the rack and pinion teeth and rubbing surfaces and grinding them down to tight tolerances instead of buying new parts.

Steering is tighter than when new. I guess that's enough bragging on myself for one day!

I was mowing my lawn last night with my L120 and the blades stopped rotating while I was going forward. I went into reverse and pressed the RIO button and the blades engaged again, but only in reverse. Messed around for half an hour mowing in reverse but cannot get the blades to engage in forward. Any ideas?

k8schulze, you have a broken wire going from the pto clutch, most probably at the wire connector at the clutch. Just get part number for the wiring harness at john Deere parts catalog and buy it at amazon or fix the broken wire yourself.

Got it fixed last night and works fine. Thanks!

Wire was broken at PTO harness near front of tractor. Have a 2003 L120. Had already replaced PTO and seat switches. Was very hard to get to and see, but my son's troubleshooting skills paid off! Only cost was $35 for both switches, which I didn't need but could not return!

As cbobula stated above, 180 degree turn of wires caused eventual failure. Poor design by John Deere!

Are you aware of this with the L120 manual

http://manuals.deere.com/cceomview/OMGX21647_K3/Output/Index.html?tM=HO

I don't know if you have the manual but you do now

had same problem with 2003 L120. Started out having a problem with RIO, then the blades wouldn't engage. One of the black wires from PTO switch was severed at the socket to the clutch. Removed socket, pried out the connector, stripped the end of the broken black wire, and reattached (soldered just to make sure since the connector was a little mangled due to removing old nub of wire). Works perfect, including the RIO working as it should.

Have same problem. Have checked every switch with ohm meter. Finally traced down white wire going to magento kill and cut it. Motor shuts off when you turn switch off due to fuel cut off. Really want the safety feature that kills engine while blades are engaged if you get off seat. Maybe ignition switch is what I am thinking. Problem started after pressure washing mower. Giving it to my son and want the safety switch to work.

Yep pressure washer and tractors don,t mix well , compressed air and damp rag when required .

Don’t really need comments on what not to do. If you can’t solve the problem please your opinion to yourself. Thanks so much

Well not my opinion rather common sense , however since you don,t have better sense than to expose electrical circuits to high pressure water then don,t ask stupid questions ! You will have to check every interlock or connection that you have probably shorted out or loosened . Since you apparently have a multimeter do a continuity test of the electrical circuits both Primary and Secondary to verify no open circuits . Prior to testing confirm main fuse to ignition switch is functioning . P.S. In the future think before you act and park your attitude at the door , Thank you very much !

I guess I didn't understand that you had a question. Clarify please or start a new post along with more specifics of what is happening and what has been done.

Found the problem. After market wiring harness had ground and switch leg from seat switch spliced together inside plastic sheathing . And no, I was not exposing high pressures water to wiring.

Good to hear you found the seat interlock fault !

Good find. Most don't even know that some of these have the tamper proof spring in them. Though I haven't seen an aftermarket harness myself...

I had the same issue with my L120. PTO started going in and out and finally died while mowing. I was not able to get the blades to spin in reverse, but if I did get off the seat the mower would start as the engine cut out. Most people mention ground wire. I went to the front of the tractor and looked at the PTO. There is a wire harness on top of it with 3 wires. 1 hot and 2 ground. I pulled the connector off and found one ground wire was not connected anymore. It looked like the two black ground wires are crimped into the connector together. I soldered the 2 black wires together and everything works fine now.

W gogoing up a hill my blads kick out the megnet is kicking out but only on a hill