Originally posted by JimBlake
You might want to figure out why it's so hard to move in the first place. Unhook the cable from the valve on the firewall, see if the control moves easy. If so, then it's the valve that's sticking. Or unhook the cable at the end inside the car. Maybe the cable is kinked so it doesn't slide nicely. Dont replace the parts that aren't broke.
I agree, also check the valve (below the glovebox, slightly more to the driver's side from center) to see if there is anything lodged in there and remove it.