John Deere D 170 PTO

[lstra]

PTO switch suddenly starting working backwards, PTO engagement knob pushed down was blades not turning, pulled up engaged clutch for blades to turn and mow. Works in reverse order now, down for PTO clutched engaged, which the switch knob has to be down for starter to operate to start engine, thus blades are turning. Pull knob up and blades stop. Would problem be PTO switch? Any help appreciated, thanks.

 

[T.R.K.]

Its an electrical problem. (But you knew that.)
Was there any 'event' that happened to this mower about the time you noticed this change? Like maybe running into a bush or having a stick jam in under the hood, or something like that.
It sounds like the wires got swapped in the plug on the PTO switch.

You haven't offended any of your neighbors, have you?

 

[lstra]

Don't think anyone would have come in garage and changed wire leads in plug receptical that plugs onto pto switch. I might try a new switch to see if that is problem. Thanks for suggestion.

 

[Mule Meat]

The PTO switch controls more than just the PTO engagement.
Try a new switch. But it must be one made for your model and year. Just any switch will not work for the wiring connections must be the same.