Yeah. it doesn't work that way. I assume you were looking for a signal that is grounded when the parking brake is applied. The LS has no such signal. You may have to rig a manual switch, or do a parking brake bypass for the aftermarket radio.
Which connector did you mess up?
The one that goes to the parking brake? That one is in the trunk at the parking brake electronic module on the driver's side side wall, near the brake lights.
The one at the parking brake actuator? That one is under the car at the rear axle.
The one at the parking brake set/release switch? That one is in the floor console.
Again, none of these have the signal that you need. I'm very curious as to how you were going to hook anything up without the pin-out that you say you need...
I have the pin-outs, but I have to scan in a printed copy, so let me know which connector so that I don't waste time on the other ones.