A hydraulic control system that includes a solenoid valve for supplying a
prescribed fluid pressure; and a relay valve for selectively switching a
destination of the prescribed fluid pressure between a first destination
part and a second destination part. The relay valve has an input port
supplied with a normally produced fluid pressure and an output port that
selectively communicates with the input port. The hydraulic control
system further includes a fluid pressure switch, provided in the output
port of the relay valve, that is activated when the input port
communicates with the output port to allow the normally produced fluid
pressure to be supplied to the output port.