Need help wiring reverse camera

[pete118]

Ok i’m new to this but.. I have a seat ibiza mk5 and a pioneer sphda120 head unit. I’ve wired the unit up everything’s working fine. But I’ve bought a reverse camera and decided to give that a go wiring up. (Pumpkin camera off amazon) I’ve set it up so the black/red wire is on the purple/black reverse light so it is getting power when in reverse. The other wire I’ve spliced it to the brown wire on the reverse light loom. (Even though with this wire not connected camera still works in AV) The headunit has one of them canbus looms something to do with the steering wheel or something, it has a purple with the tag ‘reverse’ so I’ve spliced the red wire at the front end of camera wire to that. (There is also a purple wire coming from the head unit saying same thing) which I’ve left, I’ve put the yellow rca into the one at the back of unit that has a yellow one saying ‘reverse video input’ I go in reverse nothing happens. But if i go on settings to AV the camera comes up. I’ve tried changing settings polarity ect and nothing’s happening. I really don’t want to manually press the screen when I want to reverse. Any help would be appreciated