When shifting into manual, the car would go into whatever gear you were currently in, but would not shift up or down.

I had played with it since purchasing the car, so I knew that it had worked previously. I wouldn't have been too upset about this revelation, if it weren't for the fact that I was currently driving down a 13% grade mountain pass when I found out it didn't work. I needed to shift down, or ruin my rotors. Luckily I found a place to safely pull off part way down the pass to let my brakes cool before going the rest of the way down, or the problem would have been far more severe to me. Definitely frustrating none the less.

The fix was fast and relatively easy for them to do, they just switched the whole knob out, and that fixed the electrical problem there. They talked with GM to see if it had been an issue in the Terrain or any other vehicle, and at that point it hadn't been. Guess I'm just lucky that way!