OK, so cruise control is affected by more than a few things: brake switch, third brake light, torque converter, etc
That line is PCV valve vent line, and all it does is vent excess crankcase pressure into the intake. You can block that off at the intake side and let the valve cover side vent to atmosphere and nothing will change. If there is a leak you get a lean condition since the leak is after the MAF but before the TB.
EDIT: do you have a "brake switch b input circuit low" code stored? Doesn't throw a CEL.
