Buy a new remote, most these days can be cloned from another remote, then use the new one to try the receiver. Also check that the receiver is set for your remote most have program or learn button that you press on the board then you press the remote transmit and it learns the code, I have seen many instances of the receiver or the transmitter forgetting the code due to power glitches or battery failure. All the control boards that I have used have an led on them that flashes when the signal is received from the remote so this will tell you if the transmitter is sending and the board receiving the signal.