John Deere 455 pto problem

I have Deere 455. While mowing grass on Sunday, the mower deck shut down. Because I was on a steep grade, I thought that I had come out of the seat, causing the deck to shut off. I pushed down PTO button and raised it but nothing happened. At the same time I noticed the tractor was running very hot and went back to the garage to blow out the radiator. After blowing out the radiator, I started the tractor again but still no PTO. We checked all fuses and they all are good. We took the seat and fenders off to get to the brake switch to check that. We were able to jump across a couple of the contacts on the brake switch plug and make the PTO start turning. I bought a new switch installed it and the PTO still won't engage. Is there anything we are not thinking of? We removed the new switch, jumped a couple of the contacts and again, the PTO took off. Is it likely that the new switch was also bad? Thanks for any help.