squeak in emergency brake

I have an '01 Silverado. Been hearing a squeaking sound coming from under the dash and have isolated it to the parking/emergency brake. When the brake is pushed in the squeak goes away but once it is released, if you move the truck at all it squeaks. Anyone have an idea how to remedy? I tried pushing on different parts of the mechanism to see if perhaps it was rubbing somewhere but no luck. I suspect that it is the actual cable rubbing against the cable housing. Any one else get this?

In case anyone cares...I pulled the kick panel and found that the rubber grommit that surrounds the brake cable as it passes through the firewall had slipped up and allowed the cable to rub against the opening. A little contact adhesive and no more squeak! (For now...until the next one :)

Good troubleshooting.