Ok after after around I never found anyone who had installed seat heaters in cloth seats for 3rd gen 4runner and people asked if I did it to post some pics.
I had installed them in out 2012 tacoma and found it super easy, with lot of information online about it. So here is some info our our seats.
I found it super easy and after doing it I found it almost easier than the tacoma. All I had was pliers and snips to cut or twist off the metal hog clips. Most of the Hog clips are on the button and I only needed to cut 2 on the seat butt.
under the seat you will see 8 rings total. 3 on each side and 2 on top.
Close up of the hog rings.
You have to remove the plastic side pieces to access 4 bolts that allows you to remove the butt part. This is done by a few phillips screws and the manual lumber knob has a clip in the handle. I pushed the plastic hard to see the clip and pushed it off with a screw driver.
Once the side plastic and the 4 bolts are gone the butt cushion comes right out. I placed it on my work bench to better remove the 2 harder to reach hog rings.
I cut the pad to size and stuck it down on the seat.