not to say those don't work........... BUT, there's a little grey plug under the seat......... UNPLUG IT.

some will say this has to do with the electric control seats. so far i've disabled all of our work trucks, 05 F550 (electric seats), and (2) 03 F250's (also electric seats) with a simple unplug of a connector. there are typically TWO conectors under the seat, one for the electric controls and one that closer to the seatbelt (female end by your right hip). it may be a trick to find at first, but it will do the trick. all the ones from the trucks i listed above are a grey colored plug.

i did the same thing on my 02 Ex (XLT non-electric seats), and my F250 Lariat (electric seats), no more alarm, and WAY less time!