No large fuses in these trucks. Verify voltage is getting through the battery connector. Check the voltage on both sides of the main contactor. Should be about the same, if not check the PTC, that is the orange or red discs that connect to the large cables on the contactor. these allow voltage to keep the capacitors precharged in the motor controllers. They should be warm when you touch them. If this is all good you may have a bad Master controller.