Garrett - whose yardage total was a career high - carried 4 yards to score, finishing a six-play, 79-yard drive to give the Wildcats a 13-3 lead with 10:04 remaining in the second quarter. Not even two minutes later he scored on a 21-yarder to make it 20-3.
Weber State (5-5, 4-3 Big Sky) outgained the Aggies 479-174 on offense.
C.J. Spencer finished 15 for 28 for 146 yards and an interception for the Aggies.
Brady Stuart connected on a 52-yard field goal for the Aggies (1-8, 1-5) for their only points.