Because the driver's seat is the most complicated component I decided to explore it first. The system that operates it seems similar to the system that is in my C63 seats. It also has some characteristics of the 986/996 memory seats in my Boxster.
The seat connects to the car with two harnesses. One is connected to the seat using a large yellow connector. The other connects to the computer module under the seat:
The harness that the recycler included when I purchased the seats appears to be from a car equipped with different seats. The yellow connector fits fine, but the second connector on the harness does not fit the computer module:
You can see in the top right that the second connector is almost square compared to the rectangular socket on the computer. The recycler must have given me the pigtails from a different car.
I plan to contact the recycler to see whether they can send me the correct harness.
I connected the power and ground of the yellow connector to a 12-volt power source. As I expected this did not allow the seat to work. My theory is that I also need to provide power and ground to the control module. I expect that the largest terminal on the computer module is the power and one of the terminals next to that is the ground, but I am proceeding with caution to avoid damaging what is likely to be an expensive component.
You cannot see it in any of the photos, but like the memory seats in both my Boxster and C230 Mercedes, each seat motor in the 997 driver's seat has 4 wires connected to it. One set of two wires provides controls the seat motor from the memory and the other two provide control from the switches on the side of the seat. If the seats are like the ones in my C230, the air bladders in the bolsters and the lumbar support are not controlled by the memory.
There are a total of 4 sockets on the control module. In addition to the empty socket that attaches the module to the car, there is one that I expect has connections to the seat motors. There is also one that connects to the controls on the side of the seat. I need to determine the function of the fourth connector.
I also tested the passenger seat. Supplying power and ground to the connector is all that I needed for the controls. I will need to follow TTGator/STL986's guidance for the seat heaters.
I'll continue to explore and post updates as I gather more information. Please feel free to pass on suggestions.