First I have no idea of what I am talking about, but if the circuit is controlled by a relay switch the only way you could check it, is to the check the output from the relay itself not the switch that controls the relay.

What I am trying to say, and this for an example only, If the seat Switch controls a relay that interrupts the starting circuit, the seat switch may test OK. But if the relay is shot, the switch is not changing the condition of the relay. So if the relay failed in an off position, regardless of how well the seat switch worked, the relay will not change it status. ie not open to allow the tractor to start.

These things become complicated. The switches could be set up as "AND" gates or "OR" gates. In an AND gate both switches would have to be on to activate the relay. If the switches are wired as an OR gate then if either switch is activate the Relay will activate.

You need to get the schematics for the tractor wiring to properly trouble shoot the problem.

You can start here
http://www.tractordata.com/lawn-tractors/000/0/9/97-john-deere-stx46.html

or
"http://jdpc.deere.com/jdpc/servlet/com.deere.u90490.partscatalog.view.servlets.HomePageServlet_Alt";

Enter "STX46" in the box in the upper left corner. Note: in both case do not include the " " marks

Places to start would be: Verify the new battery is good w/ load test and terminals are clean at the battery, solenoid and the end of the ground cable. On an STX, you will want to know the ground strap at the engine mounting bolts is secure as well. Battery load tests are free at many auto parts stores BTW.Can you roll the engine over by the top screen- so you know it isn't seized? Your fuse is good, but look over the connectors for corrosion.
Now the basics are done. To determine whether you are dealing w/ a safety issue, shut the PTO switch off, set the parking brake / clutch and check the 2 small terminals on the starter solenoid. One there should be a ground present and the other will be 12 VDC when the key is turned to start. No ground means something is off line on the safety system. A PTO switch is a likely culprit on these as if they get left in the rain, both the PTO and starter switches and their terminals get corroded due to the location. Plus the safety line does run through the PTO switch. Another odd thing that tends to happen on these is that the harness that runs along below the seat can get caught in the deck lift mechanism. The harness itself up from the solenoid along that LH rail can be problematic as well.
The PTO clutch will have both a 12 VDC and ground when activated. No clicking could go back to that ground at the engine mounting bolt.

Tom, I tried a new PTO switch with no luck. I went back and checked ground wires, battery cables, etc. I did finally get it to crank by laying a screwdriver across the two post on the solenoid. Does this just indicate that I have a bad ignition switch? Or wire going from the ignition to the solenoid? I tested the negative battery cable to the post on the solenoid (the post with the cable from the solenoid to the starter), and didn't get 12 volts. Thanks

With the key in the start position, I get 12 volts from the negative battery post to the battery side of the solenoid. I get nothing from the negative battery post to the starter side of the solenoid. Also, I get nothing from the negative battery post directly to the starter.

If it cranks whilst jumping the large solenoid terminals that tells us that the battery, starter and ground is good. Testing from the negative post to the battery lug on the solenoid will give you 12 VDC whether or not the switch is on. You wouldn't expect to have 12 VDC on the starter or starter lug on the solenoid if the solenoid is not activating. Once you know all is hooked up as it should, (set the park brake / clutch, shut off the PTO) at the solenoid- verify the presents of ground at one small solenoid terminal and 12 VDC on the other when the switch is supposed to be cranking the starter. That will tell you if the safety switches are online (if there is a ground present) and that the switch is supplying 12VDC to the trigger wire when cranking. If you have have both of these things, from here it would seem as though the solenoid is inop.

My horse for a schematic!

IF your SOLENOID has 2 SMALL terminals, you can test it this way.

GROUND ONE of them.
APPLY 12V to the OTHER.
A GOOD solenoid will click AND crank the engine.
IF it only clicks or does nothing, it's bad.

P. 1 Deere STX46 schematic

P. 2 STX46 Schematic

Assuming a correct serial#.......

That shows the solenoid as having a fixed GROUND. No safety switches involved on that leg.

So, to test the solenoid, just jump 12V to the ONE Small terminal.

This post was edited by bill_kapaun on Wed, Feb 4, 15 at 15:47

I don't have one in front of me, but me thinks this is a 4 pole solenoid. AM104036 is the part number. Should have a purple trigger and a white ground circuit.

Tom, right again. It's a four pole solenoid. I took it off last week and had it tested at the local hardware store and was told it was good. So if that's true, perhaps it's the trigger wire? I've cleaned off the grounds and the wires look to be in good shape.

I'm a bit suspect about a hardware store testing....Did they have a load to simulate a starter motor? If it just clicks, it still may be bad.

Refer to my yesterday post @ 9:54..

You can easily test the "control" circuits to the small terminals.
Purple wire should show 12V when simulating a start. Either a voltmeter or 12V test light will do the job.
White wire should show GROUND when simulating a start.
Either OHM meter or 12V test light with the other wire hooked to a 12V supply.

I was thinking that I may be wrong on the trigger wire color. Typically the starter mounted solenoids have the purple trigger. I think some of these are black. Follow Bill's instructions on testing the input wires. You will have ground present when the safeties are in crank mode, not just when turning the key if that helps.

Ok, Tom and Bill, with the ground wire on the one small terminal, I placed a screwdriver between the large 12V cable from the battery side of solenoid to the second small terminal of the solenoid and the solenoid clicked AND the engine turned over. Based on Bill's description that would tell me the solenoid is working properly. Also, based on another of Bill's posts, if I connect the -probe of meter to the negative battery terminal and the +probe to the trigger wire and then turn the key to crank I do NOT get 12V. Is this telling me that the purple trigger wire from the ignition to the solenoid is bad? Or possibly the ignition switch itself?

Now, when testing from a ground to the red ignition switch, I'm not getting 12v. No wonder the trigger wire at the solenoid isn't getting 12v.

IF you don't have 12V to the B terminal of the key switch, the FUSIBLE LINK is bad or a bad connection of the B terminal.

Did you pull off the plug and check the plug itself for 12V?

IF you have 12V there, the FL is good and you either have a bad connection at the B terminal or a bad switch.

Usually, unplugging/plugging the connector a few times will "clean" the connection for a while.

This post was edited by bill_kapaun on Sun, Feb 8, 15 at 12:49

I'm guessing by B terminal, you mean the red wire? I unplugged the ignition switch and stuck the probe directly into the terminal of the red wire. This gave me nothing. Therefore plugging and unplugging the switch to remove debris etc. shouldn't be a problem. So I should replace the fusible link?

Is there a way of testing the FL or is everything I've done so far been the way of testing the FL? haha

B terminal is on the Key Switch.
There is a corresponding place on the connector.

IF you unplug the connector and check that part that attaches to the B terminal of the key switch, there should be 12V present if the FL is good.
Look at the schematic!

According to the schematic-
The wire in question runs between the LARGE + stud on the solenoid (the one the battery + connects to) and the key switch.

This post was edited by bill_kapaun on Sun, Feb 8, 15 at 13:43