For the toyota aurion prodigy , these are the instructions ,
there are 5 wires in the 3rd (longer) wire harness with in total of 8 connected wires
Blue with white stripe : is the wire from the reverse light (since the factory camera need 6v the use of a voltage regulator is needed) so connect this wire to input positive of the regulator
red : this is the display signal for the middle of the rca
black 1 : there are two black wires ( one for the shield of the rca , (rca outer )
black 2: this is for the camera 6v positive input from regulator
white : camera 6v negative input from regulator
(to get negative 12v power for the regulator , just earth the negative wire to the chassy of the car)