Figures it'd happen in December in Canada. Anyways, 2003 F-150 Lariat with leather captain's chairs, the heaters have the little black button on the side of the seat bottom with the orange light on it. The light comes on and stays on for the regular time period, but no heat. Neither front seat will heat up. I checked the fuse under the hood, it's good. I don't know what else to check, and my butt is getting cold!

 

it might be the heating elements, i replaced the driver side bottom on mine..but if they both quit working at the same time, thats a little odd. there is also a little relay pack or module under each seat, that could be bad, good luck..

 

i just checked more closely today. it turns out the passenger side is working, driver's side is not. all wires are connected, fuses are good. there are 2 heating pads in each seat. one is for your back, the other for your butt. if one of them burns out, does that make the other one not work too? if one of them is burned out, is it an expensive fix?

 

Its probably the heater module thats went out.