Have a 2002 nh tc 40 d that turns over and over and will not start. I changed the solenoid and checked the voltage to the solenoid . It was 12 volts. The tractor started one time and then it would not start. I checked the voltage and didn't get 12 volts. I was told to check fuel shutoff relay. Does anyone have any other suggestions in case this does not work? I have checked all the fuses and they are good.