Troubleshooting Husqvarna GTH2548 PTO

2506 Views 12 Replies 3 Participants Last post by DBH, Oct 29, 2021

DBH

Discussion Starter · Oct 17, 2021

Replaced the engine in an older Husqvarna and realized we had lost the PTO clutch pigtail. So I cut the connector ends off, and wired them directly to each other.

Tractor starts, but when the clutch switch is engaged (pulled up), the engine stops and the fuse blows. I thought maybe I reversed the clutch wires, so I disconnected those completely, and it still blows the fuse when switch is engaged.

I assume this means the PTO switch is the issue? It can’t be the clutch since I’ve disconnected it entirely. Or could it be something else?

Thanks in advance.

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SidecarFlip

· #2 · Oct 17, 2021

The electric clutch may be shorted internally. Volt meter - continuity tester time.

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DBH

Discussion Starter · #3 · Oct 17, 2021

But… if both wires to the clutch were disconnected, how could a clutch short blow the fuse?

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SidecarFlip

· #4 · Oct 17, 2021

Then you have a short to ground somewhere in the wiring harness. Time to use the meter in each one of the wires at each end.

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DBH

Discussion Starter · #5 · Oct 17, 2021

Electric troubleshooting is not my expertise - can you elaborate a bit on the process?

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FredM

· #6 · Oct 18, 2021

DBH said:
But… if both wires to the clutch were disconnected, how could a clutch short blow the fuse?

You are correct with that assumption.

I would disconnect the connector from the clutch switch and turn the ignition on to see if the fuse blows again, if not, then the 12/13 volt hot wire from the clutch switch to the clutch has a short and you could either trace that wire through and see if there is a chassis rub along the way, or you could run a new supply wire to your clutch from the switch and bypass the original hot wire.

It doesn't really matter which way you wire the clutch, one wire is hot and the other is an earth that runs back into the system, the clutch pack has a winding that feeds in one way and out the other.

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DBH

Discussion Starter · #7 · Oct 20, 2021

FredM said:
You are correct with that assumption.

I would disconnect the connector from the clutch switch and turn the ignition on to see if the fuse blows again, if not, then the 12/13 volt hot wire from the clutch switch to the clutch has a short and you could either trace that wire through and see if there is a chassis rub along the way, or you could run a new supply wire to your clutch from the switch and bypass the original hot wire.

It doesn't really matter which way you wire the clutch, one wire is hot and the other is an earth that runs back into the system, the clutch pack has a winding that feeds in one way and out the other.

Thank you! I’ve read elsewhere that if there is a diode inline (which there is) it’s possible to reverse the wiring. Regardless, since I’ve disconnected it and it still blows a fuse, it’s not that.

The only problem with your suggestion is the connection to the switch is a 9-pin connector, and I have no idea which wire goes to clutch.

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FredM

· #8 · Oct 20, 2021

Do you have a red wire that goes to the clutch?, the black wire goes to earth, black/white wire is engine kill if the clutch/brake is not locked, not sitting in the seat and the PTO clutch is on.
The only major power goes to the PTO clutch, so I would be looking for a chafe in the cable to the PTO clutch that is going to ground and that will cause the fuse to blow, the only other voltage goes to the fuel shutoff solenoid and if that is shorted, then the fuse should blow as soon as you turn the ignition on.

I wouldn't be replacing the PTO switch until I checked the wiring to the clutch and if that is ok, then the problem falls back onto the PTO switch, could have an internal short.

Is it possible to rotate the 9 pin connector that fits the PTO switch, or is this one way only??.

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DBH

Discussion Starter · #9 · Oct 28, 2021

FredM said:
Do you have a red wire that goes to the clutch?, the black wire goes to earth, black/white wire is engine kill if the clutch/brake is not locked, not sitting in the seat and the PTO clutch is on.
The only major power goes to the PTO clutch, so I would be looking for a chafe in the cable to the PTO clutch that is going to ground and that will cause the fuse to blow, the only other voltage goes to the fuel shutoff solenoid and if that is shorted, then the fuse should blow as soon as you turn the ignition on.

I wouldn't be replacing the PTO switch until I checked the wiring to the clutch and if that is ok, then the problem falls back onto the PTO switch, could have an internal short.

Is it possible to rotate the 9 pin connector that fits the PTO switch, or is this one way only??.

Hi Fred - thanks and sorry for the late reply. There is a red wire, and a black + bare that go to the clutch. I will look over the harness for chafed wires.

Good thinking about the switch; I don't know, but I also don't think it's ever been worked on, so doubt it has been reversed.

Will keep you posted.

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FredM

· #10 · Oct 28, 2021

DBH said:
There is a red wire, and a black + bare that go to the clutch. I will look over the harness for chafed wires.

DBH
Can I ask what does "black + bare" mean please ?.

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DBH

Discussion Starter · #11 · Oct 28, 2021

FredM said:
DBH
Can I ask what does "black + bare" mean please ?.

See attached pic - there was an uninsulated wire in the same jacket as the red, but terminated with the black. When I re-wired it, I twisted the bare wire + black together.

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FredM

· #12 · Oct 29, 2021

DBH said:
See attached pic - there was an uninsulated wire in the same jacket as the red, but terminated with the black. When I re-wired it, I twisted the bare wire + black together.

In your photo I can see the red/black and what looks to be a white wire, but no bare wire.

Is that the connector to the PTO clutch in your photo?, if it is, I am not sure why the white wire would be there when this is the start wire from the ignition switch, and seeing that you have this connected to the black, then this could be your short mate, you will need to trace out that white wire and see where it goes to.

I have attached the wiring diagram for you to have a look at, don't be put off by it, there is the start and run circuit and then there is the safety circuit and they work in conjunction with each other, the main wiring is red for hot, black for ground or earthing, white for start through the brake/clutch sensor and on to the start solenoid, and a black/white wire that is the mag kill wire.

Lets see how you get on with your problem.

Schematic Rectangle Font Parallel Engineering

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DBH

Discussion Starter · #13 · Oct 29, 2021

FredM said:
In your photo I can see the red/black and what looks to be a white wire, but no bare wire.

Is that the connector to the PTO clutch in your photo?, if it is, I am not sure why the white wire would be there when this is the start wire from the ignition switch, and seeing that you have this connected to the black, then this could be your short mate, you will need to trace out that white wire and see where it goes to.

I have attached the wiring diagram for you to have a look at, don't be put off by it, there is the start and run circuit and then there is the safety circuit and they work in conjunction with each other, the main wiring is red for hot, black for ground or earthing, white for start through the brake/clutch sensor and on to the start solenoid, and a black/white wire that is the mag kill wire.

Lets see how you get on with your problem.

View attachment 75535

Hi Fred - you are correct. It's white. For some reason I recalled it being bare, but I see now it was a thinner gauge white. Yes, it's from the harness to the PTO. I have no idea why it's there, but that was a factory connection.

I honestly have a hard time relating wiring diagrams to reality, but will review again.

Thanks.

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Troubleshooting Husqvarna GTH2548 PTO

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