Are you referring to the room near the end of the first level of the citadel, where the imp in the training grounds said the right lever was trapped? If so, there should be 4 levers on the northern wall together, then a 5th lever to the far right covered in cobwebs.
I clicked on the levers from left to right, then clicked on a couple more randomly and the way was open (I didn't have a character to the west to check exactly when that happened).
EDIT: I checked, pulling the levers down from left to right should work, as do other combinations if you keep pulling levers.
Beyond Divinity maps
