Toro Z Master Z355 Shutdown Problems

[NotAdamCopp]

Hello! I have an interesting problem going on with my Toro Z Master (model no. 74189):

Whenever I try to pull the right stick in to make a right hand turn, the power is cut off and the mower shuts down. If I return the stick to move forward, power comes back on. I have checked the seat relay, the brake relay, and the neutral position relays. After bypassing these relays individually, the problem still exists. The mower runs wonderfully when i go straight, or make a left turn, at any throttle position. But the second I pull the right stick back to make that right turn, power shuts off.

Sometimes the exhaust sends gunshot sounds, but other than that, the shutoff feels like a killswitch is being triggered. I'm at a total loss. Any help would be appreciated!

 

[bertsmobile1]

it is the relay or one of the switches, or the wiring between them .
It thinks, as far as a mower can think , which judging by the reactions to Covid - 19 is a lot better than most people , that you are trying to move off with the brakes still on.
As it only happens with the right stick, my money will be on that switch or the wiring between it and the relay / brake switch .
Make a pair of short jumpers with a male spade at each end then pull the switch plugs at both the RH stick & brake switch then jump the terminals .
Do one at a time.
If the problem persists then you have a faulty relay or a short in the wires between the switches.
Your wiring diagram should be at the back of your owners manual.
IF you have lost it then it is a free download form the Toro web site, but you will need all of the numbers off the ID tag
IT would greatly assist us to assist you if we have those numbers as well being that wiring often changes mid season as well as between seasons.

 

[StarTech]

Do you have copy of the wiring schematic for your particular mower that you can post? Indiscriminately bypassing relays is a bad idea, you got know what you to bypass by jumpering and what to leave open.

 

[NotAdamCopp]

Bertsmobile1: I'm making sure the brake is disengaged before moving, although in the past I've run with the brake engaged and the brakes are wearing a bit because of it. What you're saying about the brake switch does make sense though; perhaps the neutral position safety and the brake switch are both faulting and causing a shutdown? I've jumped the RH relay and LH relay simultaneously to trip the neutral safety switch. Their plugs are daisy-chained together which is why I had to jump them together. Made sure it was bypassed by starting the mower with the sticks in reverse and it started up. Tried to take a right turn and it still did the same thing. I haven't jumped the brake relay, but I'm unsure why it would be causing the issue. I'll check it out tomorrow.

StarTech: I've consulted the wiring diagram before doing all of this. I've got a bachelor's in ME and have dealt with a lot of wiring harnesses - I've attached the wiring diagram to this comment as well. I jumped SW2 and SW3 simultaneously, and I jumped SW1 independently. Let me know what you think!

 

[bertsmobile1]

Unfortunately I can not read the schematic well enough to be specific.
Thus a quick run down of the circuits
On all of the switches the external terminals protrude into the switch , The plunger has a brass tab on it which either makes or breaks contact between the facing pairs .
Some are single and some are double.
On the double ones , on side will be normally open & the other normally closed.
With the exception of the cranking circuit all of the safety circuits are usually ground circuits thus a short to ground will activate the circuit and be a PIA to find .

To crank you need neutral + brake + only on latter models seat ( 4 contact 2mm blades )
To run seat on + brake off ( so you are there )
To run sticks off + brake off ( so you don't burn up the brakes or hydros )
To get off sticks on + brake on ( so it does not run away driverless )
To get off PTO ( PTO + seat ) ( so you don't cut your own hand / foot off )

Looks like you might have individual relays which makes life a little easier .
latter models use a module combined within the hour meter which is not repairable $$$$$$ .

 

[StarTech]

Wasn't questioning your ability just need to note for others that don't. It does sounds like a loose connection in the kill relay circuit.

With what you have done it is kinda looks to be the bagger interlock, the jumper at that location, or loose wiring (terminal) especially if the terminals are Packard (F56) type. These tend to break at the hinge point and cause loose connections. A way to test this theory is to apply 12v directly to the kill relay + side ( I think it is label K2, the image is a little blurry here) and make sure the - side is grounded to frame. That should tell if the relay is dropping of not. Then leaving 12+ connected remove the ground jumper and this will allow normal the grounding thru the brake and neutral relays paths. The only the brake relay comes in play (activates) is when the brake is on which back feeds the ground of the kill relay thru the activated neutral relay. The interlock only comes in play (activates) when the PTO is off. It does gets a little confusing from here interlock relays only pulls if the brake relay is activated along with the neutral relay activation.

IF it is a grounding problem with the kill relay then got to be in the wiring or contacts thru the deactivated brake and neutral relays.

I probably been as clear as mud. My thought processes may only work for me as I having visualize this in my head.