I recently visited your forum looking for help to fix a power seat problem on my 2000 Blazer. I was surprised to see that others had exactly the same problem. The lumbar works but nothing else. All the fuses are good so I ruled that out.
My car has the memory seat feature, and if that loses it's signal it shuts down the entire system. I invested in a complete set of GM service manuals for this car and started reading. That is where I discovered the chapter on power seat and trouble shooting them. I tow this car behind my motorhome and sometimes kill the battery.

In the service manual there is a section about re-setting the memory module. I disconnected the battery, waited about a minute,reconnected the battery, and the seat began to work. I don't know if the people who posted the same problem with the seat have the memory feature, but try the battery thing to see if it fixes your seat functions.