The seat relay is in the fuse box module. remove the fuse box lid, then loosen the 4 phillips screws all the way (you don't actually have to pull them out- they'll be safer in their holes in the relay lid) You might need a stubby driver to get the screw at the base of the windshield. Pull the lid up and towards the front of the car. There is a line of cube shaped relays on the left side of the box (nearest to the engine block) The seat relay is all the way in the back at the base of the windshield - mine was a yellowish translucent plastic. To pull it out I had to 1st remove the 2 chrome relays in front of it. The chrome relays only go in 1 way (there's a plastic locating pin on the bottom).
The seat relay has 5 pins on the bottom - a line of 3 and a line of 2. The 3 pins go on the right side (nearest the fender) you can see the contact pin holes in the relay box with a flash light.