The light in the door sill, the heated seat, and the power seat work intermittently. I've only seen the door sill light on once and it was after a rain. The power seat usually won't work when you first start the car, but will start working after you get it moving down the road. Heated seat doesn't work at all. I'm wondering if all three of these are powered off the same circuit as I can't tell running down the road if the sill light would come on and really haven't tried to use the heated seat after I get moving. Any ideas would be appreciated. Thanks. Brad

 

Three different circuits.
The door sill light is in the interior light circuit, the lights that come on when you open the door.

The power seat uses a relay under the dash and it fails at times, but your problem could be anywhere in the circuit I guess. The relay works in two ways, one when the door is opened and no ignition on and switches to power on position when the ignition is switched on. You should be able to hear the relay click when you push the door closed button on the door jamb if your ears are good. I used to be able to hear it but not now. My sequence of operation for the relay may be wrong but is not too far out. It is explained in this PDF. CLICK

The seat could be a fuse or if it is just one seat the elements could be broken, bad ground etc.

 

Thank you for the info. Brad