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I have a recent problem with my MTD RTZ54 GOLD zero turn mower. While mowing and turning a corner my blades stopped turning. The mower runs, turns, and drives fine. The belts are ALL hooked up and working properly. Thinking there was a problem with the clutch I checked that first. If I jump a wire to the clutch directly from the battery the clutch engages and the mower mows just fine (I finished mowing this way, with a jumper wire, I know it is not the safest thing to so...)

Here is the weird thing, when I unhook the wiring harness to the clutch I get 12 volts at the power end of the connector with the key and clutch button pulled out (clutch button seem okay), but... when I hook up the clutch the voltage goes to zero at the wires... Okay, again 12 volts when unhooked from the clutch and "0" zero when hooked to the clutch. I am thinking there is a blade controlling nanny that might be grounding out the system, just a guess, but why does the juice go away when I hook up the clutch (which works fine with a jumper) ? I am thinking it needs to be the seat pressure control (don't think so), the reverse "blade shutoffs" but there are two and I don't think both would go bad at once, or... I am open to suggestions. Have anyone had this experience ?

You need both a power and a ground to make a circuit.
Did you check them both at the clutch plug ?
Most clutches are isolated electrically from the mower so have no ground other than the wires.

There are two wires running to the clutch. I assume one is the positive and the other is a ground. Both the positive and the ground seem to be working at the clutch plug or junction that separates the clutch wiring from the tractor, in that it makes a complete circuit at the plug and shows 12 volts. I have no way to check it at the actual clutch. The wires are internal at the clutch. When I run the wires to the clutch from the battery (both a ground and a positive) the clutch works fine. The clutch appears to be grounded through the second wire and it works fine when I "hot wire" it, so to speak.

The burning question is where do you connect the jumper to ?
Get a pair of pins and poke then through the wires as close to the clutch as you can.
The wires could be broken near the plug

I am jumping through the connector in the electrical line to the clutch. I guess my question is if a wire was broken internally near the clutch then how is possible for me to use those same wires to go straight to the battery with jumper wires and the clutch works fine ? If a wire was broken internally then I should not be able to "hot wire" the junction to the battery through those same wires and have it run perfectly. The wires to and from the clutch appear to be fine.

How do the "safety" switches that stop the blades when I back up or get off the seat operate ? Do they simply shut off the current to the clutch or do they ground out the electrical system to the clutch ? I had seen info online that some of these "safety systems" are a live circuit that breaks the current when the safety switch is activated and some simply ground out the circuit. If one of these switches was bad I am wondering if it could be grounding out my circuit to the clutch. I wonder which the that MTD used ? Everything else runs perfectly. The blades seem deactivated.

I am tempted to start unhooking to safety switches to see if anything changes.

if your mower has the switches that activate when you pull both handles back to reverse as back up and the pto disengages one of the reverse switches may be defective. Does the pto disengage when you turn only one direction example say left? For example if the right switch remains activated and you turn left both switches are closed and machine thinks you have activated reverse operation

Because I am not totally familiar withthis mower, I need a bit more detail about the clutch & exactly how you are jumping it.
Clutches come 2 ways
One has a pigtail hanging out of the clutch body , which usually connects to the mower via a plug near a hole in the mower floor.
The other type have a socket built into the clutch & the mowers wiring plugs into it
Which one do you have ?
Exactly how are you making the jump connection ?
Did you get another plug "
Strip back some insulation ?

Because the terminal pins on most are too close together to use clamps
I am having trouble visualizing what your are doing .

NorthBama said:

if your mower has the switches that activate when you pull both handles back to reverse as back up and the pto disengages one of the reverse switches may be defective. Does the pto disengage when you turn only one direction example say left? For example if the right switch remains activated and you turn left both switches are closed and machine thinks you have activated reverse operation

Click to expand...

My mower does have a push switch on each handle that will disengage the pto if BOTH handles are pulled back at once. If only one handle is pulled back the pto remains engaged. I thought about unhooking the switches, but it would seem that the pto would still operate if only one switch went bad and it is unlikely that both switches would fail at once. So I have left them alone for now.

Would unhooking the switches disable simply disable them on a MTD mower ? Do you know ? What happens when you push the switches with the handles pulled back ? Does it cut the current to the pto or does it activate some sort of ground or active system that shuts down the pto ? I don't want to unhook them and just complicate things until I know how they operate.

Thank you for your help.

bertsmobile1 said:

Because I am not totally familiar withthis mower, I need a bit more detail about the clutch & exactly how you are jumping it.
Clutches come 2 ways
One has a pigtail hanging out of the clutch body , which usually connects to the mower via a plug near a hole in the mower floor.
The other type have a socket built into the clutch & the mowers wiring plugs into it
Which one do you have ?
Exactly how are you making the jump connection ?
Did you get another plug "
Strip back some insulation ?

Because the terminal pins on most are too close together to use clamps
I am having trouble visualizing what your are doing .

Click to expand...

My mower has a clutch with a pigtail with two wires about 10 inches long hanging out of the clutch body that is connected to the mower with a pull apart disconnect so you can remove the clutch or change belts, etc. I was mowing when I turned a corner and the blades simply quit. All the hydraulics work fine. My first thought was the belt, but is it in good condition and moves freely, spinning the blades, etc.

My next thought was the PTO switch or the clutch. I pulled apart the disconnect for the wiring harness to the pto clutch and put my volt meter on the mower side going to the pto switch. I turned on the ignition and the switch and I get 12.3 volts to the end of the wiring harness while unhooked to the clutch. So that seems good.

I then assume it is the clutch or the wiring to the clutch. It appeared that the clutch was not getting any juice so I cut the connector off the end of the clutch wiring harness exposing the two wires thinking their might be a problem with the connector (I had recently taken it apart to change a belt.) I also made a set of jumper wires from the live mower side of the harness and checked them for juice. They had 12.3 volts. I then wired the jumpers to the two exposed ends of the clutch wires (where I had removed the connector). Nothing happened. I did not hear the clutch engage. I put my volt meter back on the connected wires and it reads zero voltage... nothing. Now recall I just had 12.3 volts on the mower side, but when I connect it to the clutch I get zero volts... Like something senses that I am trying to engage the pto clutch and shuts it down.

So I took the two exposed wired from the pto clutch and made a jumper straight to the battery. Snap ! The pto clutch engaged. I started the mower, attached the wires straight to the battery and finished mowing the yard. So I know the wires to the pto clutch are good. I put a 5 amp fuse in the jumper wired to the battery and it did not blow the fuse while mowing (thinking the clutch might have issues.)

The problem is that when I attach the pto clutch wires to the mower side wires (with 12.3 volts) the voltage drops to zero at the connection, like something is shutting is down the pto circuit when it senses that I am trying to engage the clutch. I have checked and rechecked the voltage and the connection thinking it can't be possible but that it what is happening.

Thank you for your time and patience in reading all this. I am fairly handy with mechanical issues and can usually sort things out, but this has me stumped. I am guessing it is an electric gremlin of some sort, but I am certain open to any ideas. I keep coming back to "what happens if once of those safety switches, that are there to protect me from myself, fails ?"

That is exactly what happens when a wire is broken at a terminal.
You get a voltage till you try to draw current.
Get a pin and go back a few inches.
Push the pin through the + wire and take readings from there.
If the voltage drops to 0 when a load is applied then there is a problem in the mowers wiring.

I can not find a wiring diagram for your mower.

bertsmobile1 said:

That is exactly what happens when a wire is broken at a terminal.
You get a voltage till you try to draw current.
Get a pin and go back a few inches.
Push the pin through the + wire and take readings from there.
If the voltage drops to 0 when a load is applied then there is a problem in the mowers wiring.

I can not find a wiring diagram for your mower.

Click to expand...

That would make sense. My problem is that the broken wire would have to be on the mower side through the worm hole and under the seat. Since I am hot wiring the PTO harness and it works I assume it's good. That makes finding the broken wire more problematic. I will probe around a bit, but I may just buy a 12 volt ON/OFF switch and wire it directly to the clutch using my 5 amp fuse let it go at that. I already turn off the blades any time that I get off the mower. These electrical gremlins can prove to be rather frustrating. I plan on running until it dies anyway. Thank you for your help.

These electrical gremlins can prove to be rather frustrating. I plan on running until it dies anyway.

Click to expand...

Never a truer word has been posted here.
Not really a good idea to run with the deck safety system by passed.
The most likely place for a break in the wire is at the plug.
This is why I use the pin through a wire trick.
If you get 0V at the plug but still get 12 V a few inches back = dud plug terminal.
Being a rider of shakey old motorcycles reinforcing terminal / wire joints with a piece or two of heat shrink is SOP.

The clutch wires are oft not supported particularly well and some spiral wrap around them is also a good idea.
In any case, coming up to winter your way so can be some welcome shed time when SHMBO is not happy.

I will tinker with it as I have time. Thank you for all your advise and research !