Troy Bilt PTO problem

I have a 50 inch Troy Bilt zero turn mower.Problem started when going into reverse,blades would stop,safety feature,but when returning to forward would not restart.I checkd all wiring connections,all were clean and tight.I bupassed the stock pto switch with a simple toggel switch and everything worked as it should.I cut about 4 acres,takes about 3 hours.Everything worked fine.This last time I cut about 400 feet and turned switch off to cross my gravel driveway.After crossing I turned switch on to continue cutting and blades would not start.After checking all wiring again in 95 degree heat the pto could be heard clicking when switch was on.I cut 3 hours without turning switch off.When finished cutting I turned the switch off and just to see if the blades would start turned it back on.Nothing happened.I could hear a soft click like a relay,not the louder click of the pto.I can find no wiring diagram for this mower and the owners manual is useless.Anybody out there had this problem?I hate to pay my local dealer to pick up my mower,fix it and then bring it back.