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Granburyrob · Aug 3, 2009, 09:03 AM

I have a John Deere riding mower 100 series model #gx155ca026001. The blades will not engage when I pull the knob next to steering wheel. I checked belt and nothing is jammed. I was mowing some thick, tall grass prior to this. I took belt pulley covers off and there was a lot of grass jammed in there. I removed the grass but it will not engage. What do you think my problem is?

crigby · Aug 3, 2009, 10:03 AM

Hi,
The harness to your PTO clutch is on the right up inside the frame beneath the engine. Check the wires. I have not seen problems on a 155C (thank you for giving the serial #) but some did exist on previous models. If those appear okay, go further back on the same (right) side tracing the harness that goes to the seat switch. There is a rear harness that has given troubles because the seat switch has two circuits and damage to the wires can affect what the machine "thinks" i.e. is someone on the seat.
Peace,
Clarke

Granburyrob · Aug 3, 2009, 01:59 PM

I posted a previos question about mower deck not engaging. I checked all the wires and no chafing or cuts. All plugs are secure as well. How do I check the seat switch and the PTO switch? The mower deck still will not engage. The mower does turn off when running when I get off seat. Series 100 model 155ca GX155CA026001.

crigby · Aug 3, 2009, 09:20 PM

Hi,
First, I merged the questions because I will get an email notification if you add to a thread I am already involved in.
There is no schematic available for free. How many wires go to the seat switch? Colors? I can tell you that the blue wires to the PTO switch turn the clutch on. Are the others white?
Peace,
Clarke

Granburyrob · Aug 4, 2009, 02:09 PM

Sorry for the delay

Seat switch has 3 wires: 1-white w/black stripe,
1-solid black, 1- black w/white stripe

PTO switch has 7 wires: 3-yellow, 1-white, 1-white w/black stripe, 1-purple, 1-purple w/white stripe. No blue wires

Rob

Granburyrob · Aug 4, 2009, 02:23 PM

Hey Clarke,

Could it be the electric clutch itself. Is it possible it burned up under high load of tall grass.

Rob

crigby · Aug 4, 2009, 02:58 PM

Hi,
I have to say first that I have not had any need or opportunity to electrically troubleshoot a 155C, nor have I ever seen the schematic. I can get a parts picture if the harness but it is of no help.
I kind of expected two or four wires at the seat. With three I would guess that the black is common to both sides and that checking one side will be open and the other closed with nothing (no one) on the seat. They should reverse with the seat switch laden.
The purple wires should be the clutch wires and the switch should be open on those connectrs when off and closed when it is on.
Clutches can be checked by applying voltage to it; it should clunk as it engages. I would say the solid purple wire is positive.
We will go further if need be.
Peace,
Clarke

Granburyrob · Aug 4, 2009, 04:18 PM

I took the clutch off and found a broken wire inside the plug. I fixed the wire and it now runs.

Thanks - Rob

Steven Frazier · May 13, 2013, 09:07 PM

My John Deere Hydrostatic Riding Mower will not engage the mower Blades. It was working beautifully when I mowed through some thick leaves and it threw the belt off. I replaced the belt and when you engage the Mower Deck it moves up slightly but not enough to engage the mower. Why will it not work now? Is there a key way that is part of the assembly or what could be my problem? I know the belt is installed correctly. When pulling the switch up you can see and hear the attempt for the blades to engage. Yet, it still will not turn the Mower Deck on. What can I do to effect the repair? The fuse is OK! It came on one-time and has not since. Please advise what to do or check so that I can engage the mower assembly.

Thank You,
Steven L. Frazier

crigby · May 16, 2013, 02:17 PM

Hi,
Sounds as if something is locked up and not allowing it to engage.
Peace,
Clarke

MikeInVa · Jul 18, 2013, 06:51 AM

I've a JD LX172. Its been running wonderfully since a friend basically gave it to me last year. Last week, while I was mowing my yard (the grass couldn't have been more than a couple inches high, so it's not like I was in heavy grass or anything), I noticed that with the mower blades engaged, the engine would run really rough and I would have to slow down to nearly a crawl to avoid stalling. With the mower blades disengaged, the engine runs fine and you can go speeding off across the yard at max power. Whatever the problem is, it seems to be directly associated with the blade mechanism. Anybody have any ideas?

mwomick86 · Jul 19, 2013, 06:05 AM

My John Deer LA 145 would not engage the blades while the engine was running. I check all the wiring harness and things seemed to be fine. I found nothing broken.

When I would slightly pull up on the PTO switch I would notice the engine "kill" right before the blades started to engage, so I was sure it was a safety switch issue. (turning ignition only on and pulling the PTO switch up I could hear the electric clutch engage so I knew the clutch was working)
Finally decided to replace the safety switch under the seat, even though the engine would start fine. It worked! Apparently the safety switch under the seat also controlled the blade engage. The old switch was allowing the engine to start but not the blade to engage. The new switch was only $10 from my local JD dealer.

Hope this helps someone save some time and frustration.

ktrnusa · Apr 26, 2014, 01:03 PM

Hello Rob, my name is Cathy and I am no mechanic but mechanically inclined, I am a nurse... lol... I took seat off checked switch and all connections, all looked good all wires intact everywhere where I saw you posted to other gentleman. I do hear PTO switch "kind of" click when I pull out to engage but blades don't start. Could switch still be bad? Checked everywhere PTO wires you described went and all are intact.

Was mowing and running just fine and heard a click and blades stopped turning... thats my story. Any advice please??