JD 345 PTO will not engage

[PhilTros]

**This thread/message is also posted on TractorByNet. I joined that forum before I found this one.**

Hi all. I'm new to the forum but have been reading posts for a while.

I have a John Deere 345 lawn mower and I can't engage the PTO. A little background might be in order:

Last week while cutting grass, the mower just quit running. No reason, it just quit like I turned the key off. Gas is ok, oil level ok, all fluids ok. Changed the spark plugs, changed the fuel filter, cleaned the air filter, no help. After reading the forum, changed the Time Delay Module (P/N AM128906, $19.23) but still no help. Next, I changed the Ignition Module (P/N AM132500, $96.17). Original Ignition Module had no LED's, this newer one has 2 LED's on it: one red and one green. This will come into play later in the story. This time mower started right up! Back in business. Started cutting grass again but after several cycles of the PTO on and off, it would not engage any more. Talked to someone at an online parts store and he said that with the engine off, you should hear a clicking sound when you pull up on the PTO switch. Tried that, no clicking sound. Figured the PTO switch was bad so I ordered one from the local John Deere store, it'll be in tomorrow morning (8/9/12)

UPDATE on Thursday, 8/9/12:

Changed the PTO switch (P/N AM127394, $18.64). Pulled up on the switch and this time I heard a clicking sound! Great! Also, now both green and red LED's lit up. Put the deck back on and PTO engaged, blades are turning! Finally. Started cutting grass again. However, after 10 minutes or so, blades disengaged! Tried engaging PTO with switch and got nothing. Opened up hood, looked at Ignition Module and now only green LED light is on, no red. Does anyone know what the red LED light on the Ignition Module means? When is it supposed to be on? When is it supposed to be off? Apparently, it has something to do with the PTO switch. Any help will be most appreciated.

Thanks,

Phil

 

[bigJohn3]

I have a similar problem with my smaller JD LX178. The light comes on showing that the battery is not charging. When this light is on and while the engine is running , the PTO will NOT engage, I have found a short in the wiring and it is where all the wiring bundles together to form the harness. I can move the wiring and get the light to go out and then I am able to engage the PTO. I have had this problem for some time and did not know why I could not engage the PTO. and this was happening before the charging light was coming on. I replaced the PTO switch and had PTO checked, nothing! I found the problem by moving the wiring around to check for loose connections. I will have to check indiviual wires until I find the short. This might be your problem too, for all the vibrations from mower running, must cause problems with the wiring , and I have determined a design problem with JD's
John

 

[PhilTros]

UPDATE Friday 08/10/12

Problem solved! I think the original problem was a bad clutch. As I said in the original message, I replaced the Time Delay Module (no help), the Ignition Module which allowed me to start the engine and cut grass for about 5-10 minutes before the blades stopped turning. I think it was at this point that the clutch was shorting out thereby frying the original PTO switch. Replaced the PTO switch (first time) and blades engaged but again, it only lasted 5 minutes. Called local John Deere shop and they immediately said that the clutch was going bad and I probably fried the PTO switch that I just installed. Bought a new clutch (P/N AM 131779, $215.28) and ANOTHER PTO switch and now I'm back in business!

Thanks for the replies.

Phil

 

[BigBlueEdge]

I have a similar issue to this on my JD 345.

I've ruled out the switch and the electric PTO clutch. PTO clutch is not getting +12V when engine is on, switch is on, seat switch depressed. When I jumper wires there and give the PTO clutch +12V it turns on fine. I've replaced the dash switch but that doesn't resolve it. Looking at the wiring harness I see no physical problems nor is anything disconnected. Seat switch is fine too.

So, what else is involved with the brains of sending power to the PTO clutch? There is a small circuit board on the right side of the battery that looks like it is where the PTO clutch wires go to. Is that my culprit?

This is a 1997 JD 345 lawn tractor, btw.

Thanks,
Rob

 

[motoman]

Big Blue, Wires corrode and break internally. Use a test light and wiggle the suspect wires around. Any pin connectors are suspects inside. They corrode , burn and break. If necessay eliminate the connector and hard wire (solder splice) direct. Bypass and route new wires if nec.

 

[BigBlueEdge]

Further testing has shown that the wiring from the PTO pigtail, ignition/interlock control board, and switch are fine. The switch is fine. It's just that there isn't 12V coming from the control board. Fuses are fine too. Since everything else works for the ignition functionality and other safety mechanisms I'm going to say that the control module has bit the dust regarding the PTO functionality. It's an $80 risk to replace it, but the alternative is a trip to the dealer that I know will cost $250 or more.

Rob

 

[BigBlueEdge]

Update:

It was the interlock control board. Replaced that with a $70 new one I got off of eBay and everything is back to normal.

Thanks,
Rob