Relay Suggestions for 2013 Cadillac Escalade Power Step Retro Fit

I've acquired a set of OEM power running boards for my 2013 Escalade and would like to get some suggestions about how to tackle retro fitting these to my truck. There is an old post of someone who's successfully accomplished this mod with the help of another member who custom made a control module. Ive attached the OEM wire schematic with a detailed operating description. The steps came with the OEM step assist module which will accommodate everything except the GMLAN wires. My understanding is that these GMLAN wire communicate with the BCM which deploys and retracts dependent upon the state of the door. Which leads me down trail of skimming threw the install directions for the AMP Research running boards, which take advantage of the door pin ground switches to determine the open/closed signal to retract or deploy. I'm wondering if I were to connect the running board motors to the step assist module using a bench-top power supply if sending a ground signal to the GMLan wire would trigger the steps to unfold since the only missing piece is some sort of trigger? Otherwise I have 2 PAC TR7's and a bunch of 40/30 amp relays. Any suggestions would be greatly appreciated. Resources: Step/Running board wiring schematics PDF

It says the GMLAN line is a serial data line. If that is the case pulling it to ground wouldn't do anything, you would need to send it the correct serial commands. I've never seen someone install OEM boards with the OEM module. My understanding was that all the controls for the boards were integrated in to the BCM and that putting a running board BCM in to a non running board vehicle was a near impossible endeavor. If you isolate the front/back doors, per side, and run a TR7 off of each side you should be able to get that method to work using relays in a 5 wire configuration. Ideally you would want the steps to deploy immediately when a door is opened and then retract a few seconds after the last door on the side has closed. I'm not sure if the TR7 can do that.Kevin Pierson