Z725 Quits on Parking Brake Release

[jmontois340]

Hey everyone.

Yesterday I had a weird issue where the mower wouldn't stay running after the parking brake was released. I took off the seat safety switch and it appears to be functioning normally.

The logic in the mower tells me to operate the mower the seat safety switch needs to be engaged if the parking brake is going to be released. But I was able to jump (I think) the seat safety switch where I could get the motor started without pressing the seat safety switch but the motor still died upon release of the parking brake.

I know that there are control arm safety switches as well. Could that be an issue where when the parking brake is released and the mower thinks the control arms are in a non-neutral position?

Any other thoughts would be great. Grass is getting long!

****Solution OPC Timer Was Bad. Part Number TD060-30500 *******

 

[mickeyd]

Welcome to OTT jmontois.

I does sound like a switch problem but sorry that I can't help any further.

 

[North Idaho Wolfman]

Yes the next best bet is the control arms switches.

 

[jmontois340]

I ran a few more tests...

I tried starting the engine with the parking brake off. No Start.

I tried starting the engine with the seat sensor not pressed. No start.

I tried starting the engine with the left control arm not in neutral. No start.

I tried starting the engine with the right control arm not in neutral. No start.

I placed a jumper wire across the wires for the control arm switches and I have the same issue when releasing the parking brake.

This leads me to believe something else might be going on because as far as the starting circuit goes all the switches appear to be doing their job.

Is there different functionality when it comes to running the engine? Just to me it seems either a two position switch is either working or it isn't.

 

[North Idaho Wolfman]

The next obvious would be PTO switch, and then OPC.
Engage and disengage PTO switch several times.

Next would be to check all fuses.
Check connection to all relays, OPC, and switches.
You could swap relays around and see if the issue moves.

How many wires are going to the seat switch?
Looks like all other switches are 2 wire?
PTO switch will probably also be multiple wires.

 

[jmontois340]

How many wires are going to the seat switch?
Looks like all other switches are 2 wire?
PTO switch will probably also be multiple wires.

The seat switch is 4 wire which was why I wasn't sure if I was jumping it correctly.

Also there's a little icon that looks something like an hour glass on the hours meter. I never noticed it before. Is there any error feedback from that display?

If there wasn't anything wrong with the mower and I stood up from the seat and tried to disengage the parking brake it would die. So it's acting like nobody is sitting in the seat which would point to the seat safety switch but that switch seems to be working otherwise when it comes to starting.

I also just tried engaging the PTO and that killed the engine as well but the parking brake was engaged and I do not know if that is the normal operation (IE you can never engage the PTO with the Parking Brake on)

Is there a "start" aspect of the electronics and a "run" side?

 

[lugbolt]

Leave the other switches alone.

Next time you're on it, start the engine and then pull back on the brake lever with your toe. Bet it continues to run just fine.

Sometimes the brake linkage sticks, usually just excess powder coating making things tight. I like to shoot some lube in the pivot points and 99% of the time that solves it.

 

[North Idaho Wolfman]

Leave the other switches alone.

Next time you're on it, start the engine and then pull back on the brake lever with your toe. Bet it continues to run just fine.

Sometimes the brake linkage sticks, usually just excess powder coating making things tight. I like to shoot some lube in the pivot points and 99% of the time that solves it.

Good info, I don't have enough experience with the "little" details on these.

 

[jmontois340]

Leave the other switches alone.

Next time you're on it, start the engine and then pull back on the brake lever with your toe. Bet it continues to run just fine.

Sometimes the brake linkage sticks, usually just excess powder coating making things tight. I like to shoot some lube in the pivot points and 99% of the time that solves it.

So the parking brake "locks" when pressed and needs to be released by pressing the small lever to the right.

Were you talking about pulling the parking brake pedal back or something else?

This is the parking brake assembly

 

[North Idaho Wolfman]

So the parking brake "locks" when pressed and needs to be released by pressing the small lever to the right.

Were you talking about pulling the parking brake pedal back or something else?

This is the parking brake assembly

I think he is saying that, as the parking brake not coming all the way up will keep the switch active making the system think the pedal is still pushed.

 

[jmontois340]

I think he is saying that, as the parking brake not coming all the way up will keep the switch active making the system think the pedal is still pushed.

Just to clarify the motor quits immediately upon releasing the parking brake. The control arms are still in neutral.

 

[North Idaho Wolfman]

Just to clarify the motor quits immediately upon releasing the parking brake. The control arms are still in neutral.

Awww good clarification!
I wonder if the parking brake switch is a dual contact switch (3 or 4 wires)?.
If not I'd be back to looking at the seat switch, if there is more than 2 wires coming from it, then it will be a dual contact switch.

 

[jmontois340]

The seat switch is a 4 wire.

Does that mean it's possible that it's working on the "start engine" side but not the "run engine circuit"??

I orderd a new seat switch and parking switch. They won't be in for a week. Not even sure it will fix the problem.

 

[lugbolt]

The switches are all easy to test. It's so easy that replacing them is really just throwing parts at it blindly, IMO.

There is also a relay under the front seat panel that can sometimes cause issues-but it's very rare, and in this case not worth mentioning.

Real simple electrical system on these; as most Kubota mowers are (with the exception of the ZG200 and ZD series).

And no you can't "jump" the seat switch. Well you can but it'll do one thing but not another or vise versa. Not going into detail, but no, you can't just simply jumper it-not even for testing. Test it with an ohm meter.

 

[jmontois340]

I have confirmed the parking brake safety switch, the seat safety switch and the ignition are all working correctly. Control arm switches are working correctly.

It just seems like the mower thinks the parking brake is still engaged. If you move the control arm levers in, it dies. If you try to engage the PTO, it dies.

I'm really at a loss here. Does anyone else have any ideas?

 

[North Idaho Wolfman]

Sound like the issue is either the one of the 4 relays or a bad OPC.
The relays are an easy check or just swap them around and see if anything changes.
Normally the OPC is rather tough to test, dealership might be able to test it, I'm not sure if the WSM covers testing that or not.

 

[jmontois340]

Thanks for getting back to me. I replaced the OPC and no change.

I did try to swap the wires around on the 4 relays to see if the problem moved anywhere and it didn't seem to.

One thing that surprised me was the parking brake switch is normally closed. When you disengage the parking brake the switch gets pressed and that, in my case, is what's shutting down the mower.

It's also worth noting again that engaging the PTO or moving either control arm out of neutral it also shuts down the mower.

I guess I'll look closer at the relays.

 

[100 td]

A wiring diagram for your model would be handy, not sure if lugbolt has access to one or not?

I orderd a new seat switch and parking switch.

Have you replaced these switches as yet?

If you haven't changed them, see below -

My preliminary searching indicates that the parkbrake and the seat switch are double pole switches. Have you tested both circuits of each switch simultaneously to ensure both contacts sets are changing state at the same instant?

General control logic for motion control or PTO operation, requires someone to be in the seat. This is common to both operations, and generally if that condition is not met then the engine would shut down. Therefore one output from the seat switch could be lacking, or an output from the park brake switch could be lacking.


Also could you test the following?
Set park brake, set both motion control levers in neutral(arms out), set PTO switch off.
Sitting fully on seat, start engine.
If it starts and continues to run, stand up from seat. What does the engine do?
Repeat test - Set park brake, set both motion control levers in neutral(arms out), set PTO switch off.
Sitting fully on seat, start engine. Whilst sitting fully in seat, release park brake, does the engine continue to run?
If it continues to run, stand up, what does the engine do?

 

[100 td]

Does your mower have a grass catcher fitted?

 

[jmontois340]

Thanks everyone for all of your help.

The problem was the OPC Timer; Part Number TD060-30500

This was a very frustrating problem but I am glad it is solved.