I cranked the windowns open about 3" today whilst at work....Then locked doors.
alarm went off twice this afternoon when someone walked within 6' of vehicle
is this normal or can i fix this?
Would appreciate advice?

 

this will be the internal sensors detecting movement and normal, there should be a switch to turn them off

 

your switch is in the drivers side door jam, right next to the truck pop.
I had the same problem on mine, it's a prox alarm for the car.
But if the wind blows hard, or someone farts with in 50 ft of your car, then it goes off very quietly since our alarm horn sucks!!!