I had an 04 f150 and it would ding at you if you didn't buckle up in either front seat. Well my 08 lariat screw dings for the passenger seat but not the drivers seat. I asked about it when I bought it and they said it just didn't do it. Well I don't buy that. Does anyone know how to make it work?

 

I copied this from another site.. But, give this a try.

"You must be sitting in the seat for this procedure. Make sure the parking brake is set and turn the ignition switch to the RUN position. (Do not start the engine.)
Wait until the safety belt warning lamp turns off (approximately 1 minute)NOTE: Step 3 must be completed within 50 seconds after the safety belt warning lamp turns off or the procedure must be repeated.

For the seating position being disabled, buckle then unbuckle the safety belt 9 times, ending with the safety belt unbuckled.
NOTE: After Step 3, the restraint system warning indicator lamp turns on for 3 seconds.

Within 10 seconds of the safety belt warning indicator turning on, buckle then unbuckle the safety belt.
The beltminder activation or deactivation is confirmed by the following sequences:
If the beltminder is enabled, this procedure will disable the beltminder for that specific seating position. The safety belt warning indicator lamp will flash 4 times per second for 3 seconds to confirm that the deactivation procedure was successful.
If the beltminder is disabled, this procedure will enable the beltminder for the specific seating postion. The safety belt warning indicator lamp will flash 4 times per second for 3 seconds followed by a second series of 4 flashes per second for 3 seconds to confirm that the activation procedure was successful.

After confirmation, the deactivation/activation procedure is complete."

 

if that ^ is wrong or you don't want to print it or take the computer to the truck. the owners manual tells you the steps to disable/enable that. (at least my 04 manual does)

 

It's in the Owners Manual,1st thing I did when I got My New 05 home from the dealer was to disable that annoying chime as it was Hunting season & I don't deal with seat belts in the woods.