I have a 97 dt466 international bucket truck that had been running just fine. Parked it in garage and would not crank next time I went to use it. Has not cranked now in 6 months. I have replaced the cam shaft sensor and fuel shutoff selinoid and still will not crank. Hooked up to diagnostics and it says external swtich. Getting fuel and oil pressure. Is it possible I did not install the cam shaft sensor correctly? Or what external switch would the diagnostic code be talking about? Please help...stumped!