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Good day all!
I am currently working on a Husqvarna YTH24V48 with Briggs Intek 724cc 24.0 hp.
Question is about the park brake switch. With brake pedal depressed it starts and runs perfectly. Blades engage with PTO. Issue is that as soon as brake is released, the engine dies. I ruled out seat switch b/c PTO should kill if seat not occupied. I have removed and tested brake switch. It has continuity as I would expect. (One pair with button out, the other pair with button depressed). With brake button in the engine runs perfectly (with and without PTO engaged. I believe the reverse switch would only effect the mower with the PTO on? Ignition switch? Ground issue? Any help greatly appreciated.
Hugh

In my opinion you are making a bad assumption. The seat switch will kill the engine when the seat is not occupied. Read page 15 of this manual. https://www-static-nw.husqvarna.com...OM/C4Q3g-CygYDqqSUkOJJmmls_K_s?httproute=True

Rivets said:

In my opinion you are making a bad assumption. The seat switch will kill the engine when the seat is not occupied. Read page 15 of this manual. https://www-static-nw.husqvarna.com...OM/C4Q3g-CygYDqqSUkOJJmmls_K_s?httproute=True

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I understand. But shouldn't a bad seat switch also kill the engine when the electric PTO is engaged if the seat is empty?

LawnWizard said:

I understand. But shouldn't a bad seat switch also kill the engine when the electric PTO is engaged if the seat is empty?

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Let me rephrase that. Shouldn't a bad seat switch kill the engine as soon as the PTO is engaged b/c it thinks the seat is empty?

jump the seat switch connector, if this fixes it, bad seat switch.

Lawn wizard, you are confusing two different circuits. Operator present circuit will shut down the engine, while reverse mow circuit shuts down the PTO. Assuming how they work will get you in trouble, read page 15, then follow Scrubs suggestion.

Rivets said:

Lawn wizard, you are confusing two different circuits. Operator present circuit will shut down the engine, while reverse mow circuit shuts down the PTO. Assuming how they work will get you in trouble, read page 15, then follow Scrubs suggestion.

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Thanks, but you're not understanding what I am saying. I read pg 15. If the operator is not present the seat switch should kill the engine when turning on the PTO. That happens. It also kills the engine when getting out of the seat without the park brake set. The issue is that with the seat occupied (with or without the PTO engaged), the engine dies when the brake pedal is released. Both the seat and park brake switch test good with an ohm meter. That was my original question

Thanks for your help.

Here is a wiring schematic for your unit. If you notice the seat switch has a double contact setup, so simple testing with an Ohm meter will mean that you need to jump one side of the switch before getting accurate readings. https://www.messicks.com/catalogs/husqvarna/yth24v48-96043018200-2013-10/figure-listing/schematic

Rivets said:

Here is a wiring schematic for your unit. If you notice the seat switch has a double contact setup, so simple testing with an Ohm meter will mean that you need to jump one side of the switch before getting accurate readings. https://www.messicks.com/catalogs/husqvarna/yth24v48-96043018200-2013-10/figure-listing/schematic

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Thank you.

I looked at the wiring schematic about a hundred times trying to see what else was in that series. I just could not see that that switch is effectively a double switch. Everyone I every replaced either worked or didn't. First time I've had one work for the PTO but not for releasing the brake (at least that I know of). Usually I test the mower ride ability before even trying the PTO. New switch on order. Thanks again for your patients and help.

Any one who has spent time troubleshooting electrical problems has learned the hard way “NEVER ASSUME ANYTHING AND DOUBLE CHECK EVERYTHING “. Finally in my old age I’ve learned patience is my friend and speed kills. Hopefully the switch is your problem and you don’t have a frayed wire somewhere.

Sounds like the treadle switch for reverse is activated. Put a little pressure on the treadle in the forward direction, or put the key switch in reverse safety bypass (one notch back towards OFF after starting. I had to tweak the switch after a large stick went between the deck and frame on my YTH22V46. My PTO is mechanical, but same principle operating design. I had to replace the treadle switch on my machine, but the problem was mitigated by putting the key switch in Reverse Safety bypass until I got the new switch. It only gave me trouble with the PTO engaged, meaning it thought I was reversing with the blade engaged. But if the machine you’re working on dies without the PTO, then the seat switch is about the only thing that can cause it. I replaced my seat and had a bit of trouble with the seat switch. The switch was fine, but the new seat was considerably harder and wasn’t activating the switch fully. Same symptom you describe, but intermittent and usually happened when I was bouncing on rough terrain. I had to tweak the switch mounting quite a bit to make it work correctly simply because the seat was harder and the switch was pushing out of the seat shell. It’s a pretty cheesy design for the seat switch and has very tight tolerance to operate the switch. Try the bypass to check the brake release and see what happens. While it’s unplugged, put your meter on the switch to see if it opens when you get on the seat. The one that closes is for the PTO safety. The one that opens is for the travel/transmission safety. Either circuit shuts the engine down by grounding the primary of the ignition coil, but on also requires the PTO to be engaged. The reverse safety only works when the PTO is engaged. The treadle switch is byassed when the PTO is not engaged, but the parking brake and seat switch are not.

Rivets said:

Any one who has spent time troubleshooting electrical problems has learned the hard way “NEVER ASSUME ANYTHING AND DOUBLE CHECK EVERYTHING “. Finally in my old age I’ve learned patience is my friend and speed kills. Hopefully the switch is your problem and you don’t have a frayed wire somewhere.

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Unfortunately the seat switch did not fix it. I tried a new switch, even tried a new brake switch, even tho I bench tested ok. I'm stumped.

LawnWizard said:

Unfortunately the seat switch did not fix it. I tried a new switch, even tried a new brake switch, even tho I bench tested ok. I'm stumped.

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But the fact it shut off by releasing the brake says the seat switch circuit is what is killing the engine. You’ll have to follow the wire harness back to see if it’s chafed somewhere.

I checked for continuity of the light brown wire from the brake switch to the seat switch. It was good. If I defeat the brake switch, the mower works perfectly. Runs, drives, PTO works as designed (on in seat, kills engine if no one in seat). I'm not arguing, just frustrated.

Old_Paint said:

But the fact it shut off by releasing the brake says the seat switch circuit is what is killing the engine. You’ll have to follow the wire harness back to see if it’s chafed somewhere.

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