Precisely, I've seen a lot of printers have a control board on the hot end to which the heat cartridge and thermistor are connected, with a ribbon cable running from the hot end control board to the main motherboard.
My printer does not have this secondary control board. There is a 1.5m wire running from the thermistor all the way to the main motherboard, same as the heat cartridge. Replacing the unit means replacing the entire connection, from unit to motherboard