I have a John Deere X595 and the blade will not engage. The safety switch for the seat works as expected when you get off the mower. It has been to two different shops. One shop replaced the blade engagement switch. It worked great for a couple of mowings then went back to being difficult to being engaged.

Hi,
It is most probably the brake switch. Deck will not engage and will shut off when brake is engaged. Switch is beneath left running board.
Peace,
Clarke