L3400 HST starting problems

[mwy]

New to this forum so I hope I am in the right place.

Have had a 2009 L3400 HST tractor since it was new. Used it this Sat to till some ground with a power tiller with no problem. Sunday tried to start it and nothing happen. Tested all the safety interlock Switches (PTO, Clutch and Seat) and all tested good.

Finally was able to start the tractor by using a jump wire from the starter to the battery. Engine now will run but if I try to drive forward or reverse the engine dies.

I think I have narrowed down the problem. There is a safety switch that is depressed when the foot pedal is in the neutral position. When the drive pedal is press forward the switch is released. The switch has four wired and I have tested the switch with the switch pressed in I have Continuity on both sides of the switch. once the switch is released no more continuity and the engine kills. If I tape the switch pressed in tractor will move without killing.

How do you test this switch

What am I missing?

 

[100 td]

Without looking at a wiring diagram, most likely, seat switch or OPC controller. Do you have a service manual, post a pic of the electrical circuit if you do.

 

[100 td]

Don't forget to check all fuses

 

[North Idaho Wolfman]

The HST switch is the issue.
The L3400 is in a class all it's own and doesn't share the WSM (AKA service manual) with other models, and there is no free or cheap download that I know of for it.
If you had the WSM it would give you the testing procedure for the HST switch.

I'll look through some of the other WSM's that I have, and see if another model shares the same switch and how to test it.

 

[mwy]

Without looking at a wiring diagram, most likely, seat switch or OPC controller. Do you have a service manual, post a pic of the electrical circuit if you do.

Don't have a service manual

 

[mwy]

Don't forget to check all fuses

All fuses checked ok

 

[mwy]

The HST switch is the issue.
The L3400 is in a class all it's own and doesn't share the WSM (AKA service manual) with other models, and there is no free or cheap download that I know of for it.
If you had the WSM it would give you the testing procedure for the HST switch.

I'll look through some of the other WSM's that I have, and see if another model shares the same switch and how to test it.

Thanks a bunch

 

[100 td]

The switch will probably have 2 simple circuits switching from normally open to normally closed. If it's switching, as it appears/sounds to be doing, I'd expect your problem to be elsewhere in the circuit, unless one part of the switch is failing and the second contact is interlocked. Here's a link to a service manual, only $14 lost even if it doesn't work out. Would be worth a try for me if I was chasing one. YMMV
https://www.ebay.com/itm/123155911997

 

[Sammy3700]

It could be the seat (operator presence switch). Try putting the PTO in gear and see if the tractor quits or not. This is a simple way to shade tree check this switch both circuits use this switch so if one works the other should. I think I am correct that the (F&R) pedal switch is for completing the circuit when in neutral for starting.

 

[CaveCreekRay]

My L-3800 had that issue and the first time the dealer did not fix it. The second time, a tech had seen the issue. Its the limit switches on the HST foot pedal.

The "lawyer switch" is so you cannot start the machine without it being in "neutral." On mine, the switches were reportedly up a short way on the front "dash" about a foot off the floor. Look for a linkage that heads up under the steering column, towards the right. My tech adjusted the switches back away so that its not near as sensitive. Problem solved.

Another cool aspect to this adjustment is you can move the machine slowly from the ground with no one in the seat. I don't know how many times I have needed to move the machine a few inches fore or aft and with the desensitized HST switches, you can do that. Just don't run over your foot. If you push the HST pedal too far, it still kills the motor.

Here is a diagram from the L-3800 HST system... I think the switch is on the upper right. Kinda hard to see and its not mentioned in this diagram! Sorry... I spent almost an hour uploading different file size and types and this was as big as the software would accept.

 

[wendol]

I had the same starting problems with my 3800.......turned out to be the HST rocker pedal.

This may not be the preferred solution for everyone, but I removed the switch, formed an L bracket over the plunger part of the switch, reinstalled it backwards using the original mounting bolt. No wires cut, jumped, holes drilled, etc. and can be reinstalled to original position/specs if the next owner so desires.

 

[mwy]

Came to conclusion that the problem is with the seat safety switch (which has 3 wires) (Apparently the spring in the switch broke and the switch always stays in the seated position) and the pedal switch. Seat switch works in conjunction with the pedal switch (which has four wires) to allow running a generator or pump, etc without someone in the seat. I will confirm once the new switches arrive and post what I find. Thanks to everyone for your feedback.


I don't understand all that I know - MWY