So I picked up my car a week ago and and it had a small leak in one tire and the head unit is dead; I knew about the latter when I bought the car. So I took it back to get my tire fixed under warranty and told them to check to see if the fuse was blown for the head unit (and I discovered the 12v wasn't working either) and the 12v while they were at it.

The tech told me he checked quickly and didn't see any blown fuses. But based on what I've read here I still think it's a blown fuse. So I contorted my body to get under the steering while and I couldn't really make heads or tails of the fuse box.

What should I be looking for? And if it isn't a fuse, what else could it be?

 

check the fuse behind the headunit, and check the ground of the headunit

 

there is a fuse common to the headunit and accessory outlet - in an AP1
it is #9 in the underdash fusebox but I'm not sure if the number is the same
in an AP2. You can't always tell by looking at the fuse, so I'd recommend
swapping the appropriate one and seeing if that fixes it. That is by far the
most likely cause of the problem.