[FrankF3]

If I recall correctly, the white wire is used for the rear PRO clutch when and if it is installed. Without a rear PTO it is not used. Something else to check it the relay on the LH side of the console. A bad relay or bad ground at the relay can cause intermittents as we as could a bad PTO switch on the dash.
On a couple of my diesels, I also had an intermittent PTO. In each case it was something else that cause the problem. On the first time I had the problem, the field coil itself of the PTO would open up when hot after about and hour and a half of mowing. When it cut out, I grabbed my meter, disconnected the connector for the clutch and measured the resistance while hot and found it open. As it cooled, it would start to regain continuity again. This one only happened once or twice a year but after the 3rd year would happen about every other time while mowing. The next time I had this was on another diesel. This time it would happen after I would hit a bump. I thought I was coming off of the seat, but that was not the case. The clip on the fan bracket was holding the clutch power lead in place BUT the connector next to it would bounce all the time. It eventually broke the wires off of the connector inside the insulation. When I connected the meter as int he photos, one wire felt real flimsy and power was still applied. A little pull test on the flimsy wire revealed the broken conductor as the insulation slipped off the crimped connector. The last time I had a problem, the connector for the reverse safety switch by the hydro lever had a bad crimp and was actually melting the insulation. A new crimp fixed that one.