L3400 safety switch problem diagnosis

[canoetrpr]

After reading some posts about people getting hurt getting stuck in a PTO shaft or driveline, I remembered that I have bypassed the operator presence safety switch.

It was meant to be a temporary fix which unfortunately remained.

The problem I had was then when I got off the seat at any time with the tractor running (no PTO engaged), the tractor would shut off.

I always set the parking brake.

My guess is that it is one of the following:
- HST pedal center safety
- PTO safety switch
- Parking brake safety switch (is there such a thing?)

Any thoughts on other possibilities? How should I go about figuring out what it is?

 

[Chilly807]

My guess would be the PTO switch. If it was the HST pedal switch I don't think you'd be able to start the tractor. Try starting the tractor with the PTO engaged (nothing on it, of course !) If it'll let you do that it's the PTO switch.

The seat switch is a 3 position type. One is with the weight in the seat, the second is no weight, the third with the seat flipped up. I had to bend the tab on the seat base slightly to get mine to work right.

Sean

 

[canoetrpr]

My tractor definitely will not start with the PTO lever engaged. I know this because sometimes when I am not around my kids will get on and play on the tractor and engage the PTO lever.

I guess this rules out the PTO switch eh?

I wonder if it might be the seat switch itself.

 

[Chilly807]

How many wires go to the HST pedal switch? If it has 3 or 4 wires, there MAY be two sets of contacts in it. One set would be for the starting circuit, which is fine in your case, and the second would be for the "run" circuit, or fuel solenoid. If the second set is duff, it would not recognize the pedal being centered and shut down as soon as the weight leaves the seat, which is what it's doing.. right?

Since you bypassed the seat switch, the HST switch will have no impact on the run circuit, if there is a set of contacts dedicated to the run circuit only.

I'd check mine, but I have no HST switch (gear drive model)

Sean

 

[Harvest Moon]

canoetrpr, did you ever resolve this? My machine is doing the same thing. Thanks!

 

[Sammy3700]

I may not be reading the question correct but, I have a L3700 and if you fip the seat up on the steering wheel the PTO will run and the tractor does not shut down. This for running grain augers or generators. I have a 13 KW generator that I run during power outages. Just set the parking brake, mash the clutch and engage the PTO. However the parking brake does not have to be set to keep it running I do it so it will not roll of with the generator. If you are quick enough when I use the finish mower or bushhog and need to get off to move something I will go to idel and as soon as I get off the seat I pull the seat up and the tractor keeps running with PTO engauged.

 

[canoetrpr]

Hi Harvest Moon:

I planned on figuring this out but I traded in my tractor before I did. The dealer said that he would not knock the value of the trade because of this as it was a minor issue.