Soon after purchasing my ’05 Vibe I noticed a complete lack of lumbar support. I knew I could not drive this car for longer than 1 hour without developing back pain. There is a ridiculously simple way to add lumbar support to the seat back.
You need a piece of furniture foam (JoAnn Fabrics) About 15†wide, 6†high and up to 2†deep (thick). Use a serrated knife, electric knife or other suitable knife to cut this piece to a profile that fits your needs.
Place it just below your ribcage to try out what works. Once you are happy with the shape insert it into the seat back. Sit behind the driver seat, lean the back rest forward and open the J-hooks at the bottom of the back rest. Push part of the front J-hook between the seat and the back rest.
Open the driver’s side door and recline the seat back all the way. Lift the cloth up and insert your lumbar foam support. Make adjustments to its location and close the J-hooks. You are done.