Seat wiring

I have a 2007 Tahoe. I want to wire upper level leather seats into a Tahoe that came with lower level leather seats. The new seats are heated 6 way. I also need to wire the second row. The Tahoe did not come with electric second row seats and I want to wire electric ones into it.

Welcome to the neighborhood!

Your best bet is to go order the wiring harness that fits the Tahoe that the new seats came out of and use them for the installation. Once you have them, replace the old harness with them. You should at that time be able to figure out how to connect the new harness to the main harness.