[Blackzx3]

When you hook up your what? deck it is fine?
Or are you talking about when you hook up your amp in the car it works fine?

Remember what I said, it is a process of elimination, you can always swap out the amp from his car into yours, and verify its function, and then check on the speakers.

If all your stuff works fine in his car, then it is likely an amp/sub failure, and nothing else. I might have a spare couple of hours this weekend let me know how things go.