If your going the diesel route, go with a factory sponsored school IMO. I think that's the best value going if you are paying for school. Deere has a tech program and Cat has Think Big. They are community College based and a lot of dealers will pay around 5K a year toward your student loans when you go to work.
Learning a brands parts and information system is a pretty big deal that probably takes a year to be good at. Dealer specific paperwork is another thing you learn at a sponsored school. If you know these things you are worth more on day one vs someone coming from a genetic school IMO. Butler Cat was starting new techs around $24.00 an hour out of school.
Most of the major brands have something like this
DEERE TECH PROGRAMCATERPILLAR THINK BIGOr, you could go in the Air Force as a generator technician
