Honestly I don't remember if there is one or two plugs under there. I do know that on my Sonoma there is a separate fuse under the hood for the heated seats (even though the truck was not originally equipped with heated seats).

 

My '04 blazer had manual buckets. I found a drivers power seat base for a couple of hundred. since the seat was trashed, when I recover it, I'll have 1 power seat, the passenger can just rough it!!!

 

Hi James. My '98 Jimmy is an LT so it seems to have most available options. Still, the passenger seat is heated but not powered!

I think it is fine to upgrade the drivers but not passenger seat.