I have a 2005 toyota tundra with rear parking sensor that stopped working any trouble shooting ideas?

Check the fuse for that circuit.there is a beeper under the dash as well.put a test light on it and see if it flashes,that means the beeper is dead.remove the switch if there is one that turns it off and jumper across it,and check the circuit from the shifter wiring to it,and also the reverse lights,they may have it wired to the reverse lights.