Certainly can be disconnected at the dash but much easier to do at the sensor, to find out remove the plug from the sensor - buzzer should go off unless the wire is earthed (I think - I disabled mine as the present engine doesn't have the necessary sensor and I'm pretty sure I had to ground it). If it doesn't go off with the wire not grounded it must be bypassed at the dash end.
Why does the not quite finished job before last always conspire with the not quite started job after next to make what you should be doing now harder?