If "playing" with the switch would solve the problem, I'd think that would be a pretty good indicator of a bad switch.
You should be able to tell with a multimeter or 12V test light if you have 12V going into AND, when it is engaged, coming out of the switch.

ronellis,
First, is your pto sw a rocker type or knob(pull up) type? If you have the rocker type, it is very old and I would prob replace it anyway. You will need the pto sw "kit" to change it over to the knob type. It comes with instructions and a new sw and wire connector.

The sw is held in the dash by 2 squeeze tabs on the underside of the dash. Be carefull of metal rings or watchs reaching under the dash, you will reach past the printed circuit board of the key sw module. Release the sw and pull whole sw up thru the dash to access the wires and connector. Using a basic 12volt test light. Probe the yellow wires for power with key on ONLY, pto sw off. You should have 12v.

Then sitting in the seat and key on only, engine off, pull the sw to on, the blue wire should have power now. If not check the pins on the sw and in the connector for corroision. If blue wire has power at the back of the sw, go down to the RH side of the frame just behind the RH front tire. you will find the PTO clutch wiring harness. There is a plastic squeeze pin in the lower frame, squeeze it and push up on it. It will release the connector from the inside of the frame. Check the blue wire at the connector for 12 volts with the test light. If ok, clip the end of the test light on the positive of the battery and check the other wire (black) in the clutch connector. The test light should light to indicate that the black wire is making ground contact.

If you have 12v on the blue and a ground on the black then its a good chance the clutch air gap is too wide or the clutch electromagnet is bad. The air gap is .015, there are 3 slots to check and adjust on the clutch under the engine.

Good Luck

Thanks for your replies. I'll have time to troubleshoot with your suggestions this weekend.

I'll let you know how it turns out.

I am having problems with my LX188 as well. The battery light was on and the pto will not start. I have replaced the pto switch and the seat switch. I also noticed that the terminal for the brown wire with a white stripe had burned a whole in the connector to the voltage regulator. I replaced the terminal and connector. The light has gone off for the battery, but I still am unable to get the pto to start. I have tested the yellow wire from the pto switch as instructed above and the test light doesn't light. Does this mean that the regulator is bad?