I'm in Korvanjund with the Stormcloacks and just passed the Ebony Claw door, but now I can't find anyway to open the gate:
I already checked upstairs and found a hidden room, but that wasn't it. So what am I missing?
When facing the gate they want you to open, turn to your right. There is a side tunnel. Follow that tunnel up some stairs and follow the hallway. You will see a pedestal to your right (which leads to the secret room you described, I believe). Walk past it to the end of the hall and turn a corner, and you will see a bridge which crosses over the lower room. At the end of the bridge you will find a rectangular room with a couple of shelves and a chest at the end. Ignore them for now, and look to your left. There will be some candles near a pull switch on the wall. Use that, and you'll be ready to continue.