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Discussion Starter #1 (Edited)
When I probe the contacts for my NC seat switch, in the up position I get a reading (Ω) , when pushed down no reading. I've looked at diagrams of the NC switch and its theory of operation but

I am stuck understanding how that NC switch in the up position is providing a ohm reading (Ω)

Based on the spring loaded NC switch (I put a red box around it) it looks like when downward pressure is applied to the button, it breaks contact with the connection. If this is true or if I have
the right idea then I get it. I just needed to see something like this to follow the logic. With the switch pressed down, that would explain no (Ω) reading on my meter. When the spring loaded switch is released, the spring returns it up to make contact with the connection. Hope I got this one right.


2451554
 

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What you have diagrammed there is a double pole/single throw switch which may be what is confusing you. It has four contacts, one set of two contacts that will be NC and the other set of two contacts Normally Open (NO). These contacts are where wires attach to.
Usually the seat switch is wired NO. This means that if there is no weight on the seat, the contacts won't have continuity, which won't allow the tractor to operate. There usually is a series of contacts of safety devices where the contacts have to all be closed for the tractor to operate. From your description, it's backwards. But that would mean the other contacts have other connections. Really need to see the schematic for your mower.

You should have an infinity reading when the switch is open and a very low reading when it is closed.
 

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Discussion Starter #3
What you have diagrammed there is a double pole/single throw switch which may be what is confusing you. It has four contacts, one set of two contacts that will be NC and the other set of two contacts Normally Open (NO). These contacts are where wires attach to.
Usually the seat switch is wired NO. This means that if there is no weight on the seat, the contacts won't have continuity, which won't allow the tractor to operate. There usually is a series of contacts of safety devices where the contacts have to all be closed for the tractor to operate. From your description, it's backwards. But that would mean the other contacts have other connections. Really need to see the schematic for your mower.

You should have an infinity reading when the switch is open and a very low reading when it is closed.

Okay, looking at my parts manual I see a Switch, seat, push button (NC) PN 7023354YP

Looks like this



Briggs and Stratton 7023354YP Switch, Seat OEM | eBay
 

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Rather difficult to find the exact nomenclature for that switch, but over on Amazon in the comments, the answers show that it is a normally open switch. Couldn't find a schematic of whatever Snapper mower you have. Test the switch (if working) on your own tractor. Attach the leads of your test instrument to each of the two prongs. Record the reading. Then depress the button fully and record the reading again. With the button up, it should read infinity. With the button down, it should read continuity.

 

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Discussion Starter #5
Rather difficult to find the exact nomenclature for that switch, but over on Amazon in the comments, the answers show that it is a normally open switch. Couldn't find a schematic of whatever Snapper mower you have. Test the switch (if working) on your own tractor. Attach the leads of your test instrument to each of the two prongs. Record the reading. Then depress the button fully and record the reading again. With the button up, it should read infinity. With the button down, it should read continuity.


If I turn on my meter and touch the + and - probes to each other I get a .0000 (continuity); same can be said if I touch my probes to the pins of the switch with the button fully up.
If I fully depress the button on the switch; I get a 1 on my meter ( infinity) Same reading if I do not touch my probes together and the meter is on.
The parts manual says it is a NC switch it has only two pins. The other switch in the parts manual is PN 7022886yp -
That one has four pins on it. Mine has just two.
 

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OK, that stumps me because that is a very common switch used by quite a few others. The other switch is likely your brake. It needs the other contacts for the tractor to run.
A bit after the fact, but what problems are you having that would make you look at the seat switch?
 

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Discussion Starter #7
OK, that stumps me because that is a very common switch used by quite a few others. The other switch is likely your brake. It needs the other contacts for the tractor to run.
A bit after the fact, but what problems are you having that would make you look at the seat switch?

Everything works okay, it is just out of curiosity that I asked about that seat switch when I put a meter on the plugs pins and the button is pressed in there is no reading. That would equate
to sitting on the seat for the engine would run. When the the seat switch button is fully up (off the seat) there is a continuity reading and the engine stops. Just trying to understand the theory as to why the lack of continuity with the seat switch pressed in (sitting on the seat) will allow engine to run. By same token, when I check condition of a fuse or old fashioned filament light bulb, If there is continuity, then power will travel through the filiment or fuse element conversely, if the fuse is blown then no continuity is detected, When is come to continuity, it seems like reverse logic with that seat switch and I don't see how lack of continuity (switch down) allows engine to run.
 

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Well here I go again , First did the mower refuse to run with the seat un-occupied when you first tried ? Or did you try with the brake/clutch pedal "locked down"? The entire "Module safety system" is designed to prevent accidents ,by grounding the engine magneto.The switch also grounds the mag ,when in "off" (different wire). There are 3 switches which have to be properly set for the engine to run , (seat deck ,and rider presence)and only the seat switch works with weight on seat. If the wire from the seat switch is closed the nag is grounded ,and the engine won't start/run. If open the mag will spark.
 

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Discussion Starter #11
This is what I found out from another source:

"When you get off the seat the contacts in the switch Close completing The circuit and shorts out the coil"


This is what I thought. This 'splains things and is the answer I was looking for.
 
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