I have a '99 F-150 XLT with non-power seats. While cleaning the truck over the weekend, I noticed some wires coming out of the floor and connecting to a harness under the driver's seat. Any ideas on what that would be for? Thanks!

 

Those wires are connected to a sensor in your driver-side seatbelt. It notifies the computer whether or not your seat belt is fastened.

 

I thought it was that as well, but why would it go through the seat?

Though if it's a bench up front, I agree...

 

Thanks for the info. It is the 60/40 bench.

 

yeah, the seatbelt sensor. There could be spare power wires in that harness not hooked up to anything. Many times they put universal wiring harnesses in some areas of the truck whether the options are there or not.