You have a break in the heated seat wires.
You can go right to removing the seat cover on the bottom seat, or further check this by unplugging the seat back and seat bottom and check for resistance on those individually.

The one I got for my 2006 Lariat cap chair : 1L3Z-14D696-AB

1l3z14d696ab
MSRP: $58.40
Core : $0.00
Price : $38.54
Description : ELEM ASY-ST CSHN HT

Depending on the age, you might want to order a new seat cushion with the element. That way you do not have to try peeling the old one off, and trying not to damage the foam. You will also notice how far broken in the foam is, and a new seat is a great thing ( IMHO ). That is why I have the info below :

Pad Seat Cushion : 5L3Z-18632A23-AA

5L3Z18632A23AA
MSRP : $116.37
Core : $0.00
Price : $76.80
Seats and tracks - Front seat components - Seat cushion pad Seat cushion pad Left - Super crew Captains chairs 2004 - 2005

 

damn this sucks. this is going to have to wait until i get other things fixed first and have more time to tackle it.

 

I have a 2007 f 150 scab and need a new driver seat foam cushion pad and premium seat cover, any ideas? How big a job to replace? I may start a thread.