Have an 08 F-150 STX extended cab. My first issue is, my truck no longer senses my passenger door opening. I can open the door and the cab lights do not engage, nor does the "door ajar" warning comes on. 2nd passenger sensor seems to be off or not working. Doesn't matter if someone is sitting there or not the airbag light on center console comes on and off as it pleases. Which is probably why I get the 5x5 tone when starting the truck. I'm kind of at a lost of where to go at this point as I'm not a mechanic or know where sensors are on this truck, and basic google searches don't really help much other than send me to this forum. Any help is appreciated.

 

Welcome.

I'm not super familiar with the older ford trucks but I believe the switch is in the door latch mechanism. This is what tells the truck the door is open and kicks on the dome lights. Perhaps the switch has failed and the truck doesn't recognize the door is open. As far as the sensor for the passenger, check the wiring under the seat for a loose connection or loose pin in a cable connection.