Reverse Module tie in for Garmin Tread

[littlesfmtv]

I put a Garmin Tread into my truck and a back-up camera, but cannot for the life of me figure out where to tie in for reverse to kick the camera on. Has anyone done this before or do you have any suggestions? This is an A1R truck. I would prefer to have it tied to reverse as oppposed to the light, so if i don't have the lights on it would still trigger the camera

 

[Ronmar]

the trans controller provides the rev signal to a relay that controls the light

 

[GeneralDisorder]

A1R schematic shows relay K25 is the reverse relay. Pin 87, wire number 490 is the 24v signal to the lighting system. Pin 85, wire 165 is the ground signal from the transmission control module to close the relay. The relay coil has a snubber circuit as it is MOSFET controlled and we don't want any inductive spikes damaging the TCM so keep that in mind.