Hey, I worked on the touchscreen at the end of the armrest. Internally at John Deere it was called GSix (6th generation). Built with Qt, WindRiver Linux, ran on a custom board (that 1"+ thick display is _just_ the monitor), resistive touch screen, speaks CAN/j1939/etc. One of the things it talked to was a buggy Bosch radio over a home-grown protocol that didn't actually expose the radio's state, so the display was forced to make educated guesses. This was a huge pain, especially WRT bluetooth pairing (at one point we had an error screen that told the user to just power cycle the radio because the display has already tried everything we could think of to get the radio back into a good state).
The contractors for whom I originally took over apparently had a contract to write unit tests, probably for a certain amount of test coverage or something. There was a bunch of dead code buried that was only executed by the tests, apparently to bump up their unit test coverage. This was one of many such horrors. We ultimately told management that it was cheaper to rewrite the thing than it was to fix their backlog of "must have" bugfixes, and it was a huge success. Still didn't fix the radio issues, however.
The contractors for whom I originally took over apparently had a contract to write unit tests, probably for a certain amount of test coverage or something. There was a bunch of dead code buried that was only executed by the tests, apparently to bump up their unit test coverage. This was one of many such horrors. We ultimately told management that it was cheaper to rewrite the thing than it was to fix their backlog of "must have" bugfixes, and it was a huge success. Still didn't fix the radio issues, however.