I purchased my '02 Dakota from my father and now have a problem with it not downshifting to first gear. I discovered my dad had the same problem when he purchased the truck and his dealer had the problem diagnosed as a bad powertrain control module and had it replaced. I am assuming I need to do the same thing and would like to do it myself but I don't know where it is and how to do it! I would appreciate any instruction. Thank You.