That is how my MT372 is as well.
Put the keyswitch back on, hooked up a battery and got the dash lights to all come on, engine cranks over, 12v to the glow plugs.
Had the keyswtich off to bench test since I was originally thinking something was wrong with it or the wiring since I measured 12v at the glow plugs in heat and start. Must have had a corroded connection too becasue the dash lights didnt work then.
Hopefully I can attempt to fire the tractor later this week.