WARNING: This page is about a different car, the 1999 GMC Sierra and 1999 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Power Seats Wiring Diagram (Sierra & Silverado)
Fig 2: Power Lumbar Seats Wiring Diagram (Sierra & Silverado)
Fig 3: Power Heated Seats Wiring Diagram (Sierra & Silverado)