Small Engines (Lawn Mowers, etc.): PTO on John Deere, john deere lawn tractor, john deere lawn

Question
I have a model 165 John Deere lawn tractor with a 12.5 HP Kawasaki engine.  When I toggle the PTO to on, the blades do not engage - nothing occurs.  Earlier in the summer, there were occasions when I had to flick the toggle switch on and off several times before the blades would engage.  Several years ago, John Deere mechanics replaced the original PTO.
How do you suggest I troubleshoot this problem?
Thank you, in advance for your advice.

Answer
These can be difficult to troubleshoot because most manufactures provide little info on the electric clutches.

Do you hava a volt meter?  

The first thing I would check is the deck, belt and blades.  Make sure there isn't anything binding preventing the blades from turning like a bad bearing or something.

If everything on the deck spins freely then start checking the clutch. Disconnect the power connector on the clutch, connect a voltmeter to the clutch the power connector and check to see if power is getting to the clutch.

Let me know what you find.
Eric