RandyT
Elite Member
Possibly faulty relay box. sometimes it may not be the seat switch but a shorted wire or faulty relay associated with that seat switch.
Husqvarna LTH130
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So the self shorting connector on the seat switch I think is what Randy was referring to. I think yours would have it. If it does, you will see a little plastic insert in the connector itself which has a tiny spring that does the shorting. If you pull that out and reconnect the switch it may work out. If not, the operator presence relay is a great next step. You can find these at any dealer or auto parts store for that matter as they are typically the same as a lighting relay.
RandyT
Elite Member
the wiring diagram that I looked at has 12v going to the seat switch from the load side of the key switch which also includes the charging system, and when you are on the seat sends power to terminal 85 on the operator presence relay. When 12 volts is supplied to terminal 85 opens the connection between 87A and 30 preventing the pedal up brake switch or engaged pto switch from grounding the ignition. It also closes the connection between 87 and 30 which grounds the electric pto clutch.
So I would say either you don't have 12 volts to the seat switch, not getting 12 volts to terminal 85, the relay is bad preventing the relay from operating, or terminal 86 isn't grounded. Or could be a possibility that there is a short between the brake switch and the relay terminal 87A in the wiring harness. The relay looks like about an inch square black plastic box.
So I would say either you don't have 12 volts to the seat switch, not getting 12 volts to terminal 85, the relay is bad preventing the relay from operating, or terminal 86 isn't grounded. Or could be a possibility that there is a short between the brake switch and the relay terminal 87A in the wiring harness. The relay looks like about an inch square black plastic box.
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The latest: My dealer said those relays never fail but has ordered one. BUT, before I took it
out, nothing worked so he's also ordered a start switch. Question: are any of all those wires coming
from the start switch related to the PTO or brake switch once it's running? Yes, the battery is all
charged up. The lights don't turn on when the ignition is turned to that position. I doubt both bulbs
failed simultaneously.
Good thing we haven't had snow lately. Can't stay luck all winter, though.
out, nothing worked so he's also ordered a start switch. Question: are any of all those wires coming
from the start switch related to the PTO or brake switch once it's running? Yes, the battery is all
charged up. The lights don't turn on when the ignition is turned to that position. I doubt both bulbs
failed simultaneously.
Good thing we haven't had snow lately. Can't stay luck all winter, though.
RandyT
Elite Member
The wire that connects to the M terminal on the key switch connects to the ignition modules(coils). That wire also has a wire that goes to the brake/clutch switch and the pto switch. Both of those wires combine back together and connect at terminal 87A on the operator presence relay.
I have only seen about half a dozen relays fail in my 22 years of working on mowers. Most due to water damage that rusted either the contacts inside, or froze the relay plunger. You should be able to feel the relay click when you turn the key on and then sit on the seat.
The headlights may not work if the engine isn't running because they are powered by the AC side of the alternator not the battery.
I have only seen about half a dozen relays fail in my 22 years of working on mowers. Most due to water damage that rusted either the contacts inside, or froze the relay plunger. You should be able to feel the relay click when you turn the key on and then sit on the seat.
The headlights may not work if the engine isn't running because they are powered by the AC side of the alternator not the battery.
I take that your dealer doesn't stock much if he doesn't have a switch or an op presents relay. I didn't look your schematic up, but typically there is a body ground for the safety line. Sometimes through a separate wire to the frame (at the tower or above the left rear wheel). Other times the ground is shared w/ the headlight circuit. In regards to the seat switch. If yours has the little shorting clip in the connector and you have jumped the connector, you've just told the system that you are off the seat...
RandyT
Elite Member
Tomplum, From the diagram that I looked at the seat switch supplies 12 volt power to the operator presence relay which when powered opens the ground circuit for the pto and brake ignition kill system, so I don't think this one has the shorting clip and jumping it would create the effect of somebody in the seat.