power/sleep button doesn't work

My iphone 3gs got wet a few months back. I took it apart and dried it out and got everything working except the power button on top and the camera.

So I ordered a new camera module and a volume/headphone/power button flex cable assembly and replaced the parts.

Now the camera works fine, but the power button still doesn't work. All the other parts of the flex assembly work, like the headphone jack, the mute/vibrate button, and the volume control.

The power button is still non functional though. It clicks very well, but nothing happens.

What could be the problem here?

Just in case it helps, I've found that one of the little flex cables that connects the display to the logic board (I think it is labeled '3') doesn't seem to really go in the way it should and appears loose. This is probably unrelated as the teardown for the 3gs seems to indicate that the '3' cable is for the ear speaker, but I thought I'd mention it..