RZT50 - PTO switch off turns on PTO?

[BukitCase]

Johnny, your comment
"Turning the mower on with the PTO engaged is not very safe and it's hard on the new starter." - tells me that someone ELSE (like the previous owner, or an incompetent dealer tech) wasn't an electrician (or had a manual for the machine) EITHER...

Cub Cadet RZT L Service manual | Manualzz

Download the above and check out the electrical section; I just dnl it myself so I'm not sure yet just how much it'll help -

I have an older RZT-50 also, has the Kawasaki motor. So far, electrical is about the only area I've NOT had problems with (and the Kawa motor, which was the deciding factor when I bought it)

I looked at a few pics of the pto switch on Amazon, only shows one side of the switch - but my over 50 years of electronics/electrical experience tells me that of ONE side of the switch has NC next to all the terminals, then the OTHER side most likely has NO beside that row - if so, that would mean that the CENTER row would be the COMMON terminal for its group of 3 -

If MTD (Cub's mfr) used conventional labels, then when the switch is NOT pulled up there should be continuity between C and NC terminals - but the 12 volt wire that energizes the PTO should NOT be on the NC. I can tell that SOMETHING is wired backward, but until I find a schematic I'm not sure WHAT - I DO KNOW that you should NEVER be able to start the engine with that PTO switch in the UP position.

Just looked a bit deeper in the above linked manual; You need to download it and check out page 22.
Also go to page 25 (schematic) - on that page, hold ctrl and shift, then push the MINUS key (right next to the zero) - this will rotate the schematic so you don't have to lay on your side to read it

Once this is done, drag the bottom scroll bar to the right til you see the page number (25) - you should see the 9 pin diagram for pto switch. Directly ABOVE the diagram is a smaller one that shows the order the pin #'s are in - HOPEFULLY, at least a COUPLE of your wires should match that drawing - but I DOUBT that the blue one you mentioned is where it belongs...

When you read this, please take a lot MORE notes and post back - if your wiring doesn't match the manual, it might get a little tricky to change things depending on how that 9 pin connector is made - some well-focused CLOSE-UP pics will likely help figure out what you have.

Good luck; just remember the reasons for the various switches, it should help you understand what MUST be connected and what can NOT be connected, and WHEN... Steve

 

[johnny1234]

The wiring at the PTO switch does match what's in the schematic for this year kohler version rxt-50, so that's why it has thrown me off. I can't see anywhere in that harness where repairs or modifications have been done. The other two pairs of terminals on that PTO switch seem to work fine because the switch has to be down for the mower to start, but that last pair that engages/disengages the PTO clutch is working in reverse so switch down = PTO on, but the safety/kill switch circuitry works normally. Doesn't make any sense to me unless the switch is bad, but I'm using a brand new switch and the original switch has the same issue.

 

[johnny1234]

I think I mentioned this earlier in the thread, but the original blue wire from PTO switch to PTO clutch has a break in it somewhere, no continuity, so a previous owner ran a new blue wire. I may just need to get under this thing to see what color wires are out of the PTO clutch, and maybe run a new pair up to the switch after confirming which terminals they should connect to and bypass their replacement blue wire and the rest of the harness which may contain hidden re-wiring/issues.

 

[BukitCase]

If everything EXCEPT the pto is working correctly, then the pto contacts almost HAVE to be on the wrong switch side - I.E., the two wires/terminals at the switch that control the pto clutch should NOT have continuity when the switch is in the down position, and SHOULD have continuity with the switch in the UP position.

Sounds like you're getting more familiar with the beast, it's definitely easier to troubleshoot ANY piece of equipment when you understand what's SUPPOSED to happen - I'm thinking your latest plan (post#13) will get you there... Steve

 

[johnny1234]

I haven't made any changes yet, but I did just now get out to the garage to investigate a bit further and now have more info about the wiring.

This is how the PTO switch is wired, with conditions tested while switch off...

Orange/White Strip-----No Slot-----Orange/Black Stripe (Normally Closed)

Yellow-----Yellow/Black Stripe-----Empty Slot (Normally Open)

Red-----Empty Slot-----Blue (Normally Closed when switch)

Both switches tested that way, but according to the wiring schematic it should be NC/NO/NO? Diagram is attached to this reply.

The blue wire runs right down to the PTO clutch, bypassing the original wiring. This was done by a previous owner and I don't yet know why.

The PTO clutch has two wires coming from it, one blue(currently running directly to PTO switch for that bypass) and one green(disappears in to main harness, should be ground).

The original blue wire in the PTO switch harness runs to the nearby RH arm reverse switch, then from the reverse switch down to the PTO(currently cut for the above bypass to be possible) according to continuity tests. According to the wiring schematic there should be two reverse switches in this circuit but I didn't confirm the other one or its status, and these are normally closed but the one I tested is worn so sometimes I have to tap it to get it back to NC after pushing its button so this may be why they were bypassed.

My guess here is that a previous owner had an issue with one or both reverse switches not fully closing after they stopped reversing, dude to the switches being worn out, so they ran the blue wire directly from the PTO switch to the PTO clutch to resolve the issue. Or they did it so they could mow in reverse.

Unfortunately I'm still not entirely sure why my PTO is engaging when the switch is down. The only explanation is that either both my switches are bad somehow and only for the part that closes/opens the PTO power circuit, or I have two of the wrong type of switches, because according to the attached schematic the bottom poles of that switch that control PTO should be normally open and if they were I don't think I'd have this issue. Thoughts/advise on how to proceed? The switch on the mower looks OEM, and the new switch is a new OEM style from hdswitch on ebay.

 

[johnny1234]

Needed to get the mower going so I pulled the red/blue leads off the PTO switch and moved them to a covered toggle switch. Now the mower starts and you can flip the toggle to turn the PTO on/off, PTO switch just stays in the off position. Not entirely thrilled about this setup, or the fact the reverse switches were bypassed, but it'll do until we decide to pull the trigger on a newer and more sturdy zero turn.