extremely off topic

ok not sure if anybody here knows about tractor trailers but im working on a 1985 cabover international its got a 400 cummins in it and i had to rewire the dashboard. now the people that had the truck before me ran hot wires and jumper wires all over and when i start the truck up it wont shut off juice to the motor when i turn it off and acts like the alternator is constantly sending juice to the switch panel when the truck ingition is off. now when i disconnect the harness from the motor to the dash everything in the dash works perfectly. but i do have juice coming off the motor still. now im thinkin that there is a hot wire hooked up directly off the battery to either the starter, the fuel pump, or the alternator and is constanly putting juice to the engine. any suggestions would be appreciated