2002 chevy venture rear windows

I'm getting ready to do an Autopage RS-1000 system on my wife's 2002 Chevy Venture, and was looking over the wiring diagram tonight, since I've got to wait for the system to get back in stock at the shop. I've got a DEI 529T that I was planning on using to close the rear vent windows (since they're power), but looking on the DirecTechs wiring diagram, I notice that it's not recommended to interface with the rear windows, so no wiring colors are mentioned. Obviously, I can come up with them myself, but does anyone know why this might be? Or has anyone successfully put a similar module on these windows and had it hold up long-term that can put my mind at ease? Or even give me some good tips on what method they used or found was used by GM in this vehicle? Thanks!

There should be no problems if you go to the motor wires but check them out first, i.e. both "sit on negative" and one or the other goes 12v+. All you are looking for is one that does that on close.

That was my thought...I was hoping not to have to "travel" that far to make things work, but that may be the only way. I may check things at the switch as well, just in case. It looks to be just a simple spdt switch in the overhead console. That would be the easiest place to go, if it would work, just due to the mechanics of the install itself, but may not work otherwise...I don't have a complete wiring diagram for the van like I do for my other car, so that complicates things somewhat. Obviously, if I have to go all the way back to the motors, I'll have to isolate them from each other (even though they work in tandem), and need to use heavier gauge wire back to the 529T. Agreed?