You will have to go from the side or underneath. Then you can unplug and remove the old pad and replace it with the Replacement 29-Volt Seat Heating Pad for Thomas Payne Seismic Series RV Couches and Chairs # 674864.
If you need to replace the entire kit you can use the Replacement Seat Heater Kit for Thomas Payne RV Furniture # 195-000113 view full answer...