With most touchscreens now, you use a rca cable kit to retain the stock backup camera. Depending on the model, the connector may be included.

Check out crutchfield. They have solutions like a sub harness that plugs into the stock harness.

 

Thanks for the tip. I found this as a match for my 2016 Corolla LE:

PAC CAM-TY12 Backup Cam Adapter

Retain your factory backup camera or add an aftermarket camera to select 2014-16 Toyota and Scion vehicles

www.crutchfield.com

It's a 24-pin connector and requires 6V, so that answers two of my questions.

Does anyone know which wire is the reverse trigger?

Thank you!

 

Thanks for the tip. I found this as a match for my 2016 Corolla LE:

PAC CAM-TY12 Backup Cam Adapter

Retain your factory backup camera or add an aftermarket camera to select 2014-16 Toyota and Scion vehicles

www.crutchfield.com

It's a 24-pin connector and requires 6V, so that answers two of my questions.

Does anyone know which wire is the reverse trigger?

Thank you!

Pin 2 on the 28 pin connector. Should be a red wire on the car side.

Check it with a multimeter with power on. Should have 12vDC on that pin when you're in reverse and 0vDC when in park.

That adapter you bought should come with instructions.