I just got a new headunit for my car and I understood that I would lose the steering wheel controls for the audio unless I get some adapter, but I also discovered that the trip computer doesn't work either now! What does the audio system have to do with the trip computer, did the car installation guy mess up some wiring or do you guys have the same problem?

You have to ground a certain wire in order for the trip computer to still work...the guy who did your install most likely didn't ground that wire. I'm sure you'll find which wire in the Audio forum or FAQ.

There is a now unused 4 wire harness back there. Ground the brown wire to get your trip back. It should be the same harness plug that was tapped for your steering wheel control adapter.