Seat switch troubleshooting

[Kpeklund91]

Hello everyone

I'm by no means an expert at this stuff, I just have a little experience in automotive troubleshooting.

I'm trying to figure out what's going on with my father's riding lawn mower
2005 Simplicity Broadmoor 20hp

It went from not turning over at all.. no crank... Nothing. I inspected visually, the wiring harness and any switches that I could. I tested the solenoid and that is also functional. After reinstalling the solenoid, the mower now starts. Hurray! But wait..

Now the mower indeed does start, but it starts regardless of the seat safety switch being depressed or not. I don't think that is correct... But I could be wrong?

checking the clutch switch(I think that's the right term)... 2 sets of contacts.. one side is open when depressed, the other is closed. And vice versa when it isn't depressed. That seems functional.

I removed the seat switch, it is a N.C. switch. Closed when idle, open when depressed. Using my meter is seems functional.

The mower starts regardless of the switches position, open.. closed.. removed or installed.. it always fires right up.
It will, however, shut off the moment the PTO is engaged. It seems to be working halfway... But I'm trying to figure out if it is supposed to even start at all without the switch being depressed and the circuit being interrupted.

I checked for continuity between the switch and battery negative and it had a solid path.. so I'm kind of at a standstill. I was told that the seat safety switch, when functional, grounds the ignition so it cannot start the engine or run the engine when it had a closed circuit, and when someone sits on it, it interrupts the circuit and allows the ignition to take place.

Am I chasing a phantom issue here?
I went from a no-start issue to the tractor starting regardless of safety switches.

Any help appreciated and sorry if my description is confusing.

Edit: I forgot to mention that the wiring harness has some issues.. so I know that could be causing some issues. When I visually inspected, the constant black ground wire that runs throughout the entire harness has been melted and almost all insulation just falls off like dirt. There has obviously been some shorts and a lot of current flowing at one point to cause this to happen...

 

[Kpeklund91]

I guess to summarize...
My mower starts regardless of seat switch position. Closed or open, it fires right up.

It will kill the engine if the PTO is engaged and I get off the seat.. so that much seems to be functioning

I am just at a loss as to why It is cranking and starting regardless of this switch
The operating manual clearly states the seat switch has to be depressed.

Any help would be greatly appreciated and thank you in advance for and advice

 

[Hammermechanicman]

Pic of how you wired the solenoid? If you melted the insulation off the wire usually means you are either pulling starter current through it or wired wrng and battery+ to ground current going through it.

 

[Rivets]

I would check the brake switch. if the brake switch is engaged the engine will start and run regardless of anyone on the seat. Unit thinks the parking brake is on.

 

[bertsmobile1]

Up untill very recient time the seat switch is not active during start up.
It becomes active once the parking brake s released
It makes it very difficult to service a mower if you can not start it unless you are in the drivers seat.

 

[Kpeklund91]

I'll check the parking brake switch. Seems logical.
I was just concerned because it states in the manual that the engine should NOT crank if the seat switch isn't depressed, And it does.
Maybe the parking brake switch is always "on" ... Thanks for the tip.

Also, in regards to the solenoid wiring... The ground wire off of the solenoid had been exposed before I even did anything to it. It was the first thing that caught my eye. It would occasionally touch against the large gauge battery positive and spark. I've already replaced that with new, shielded wiring. I'm thinking that the melted wiring in the harness resulted from that short... Only thing I can think of.