Been a long time since I worked on mine, but I seem to remember the seat cushion had 3 separate heater circuits, and was around 24 ohms total resistance ... 8 ohs per circuit. The back heater had 2 circuits, and was 16 ohms. If both circuits check out, switch the passenger side switch with the driver side to see if the switch is the problem.

Correction. I read back to some of my old posts, and the seat cushion circuit is 3.2 ohms, while the seat back circuit is 2.4 ohms.