I am creating a sumo bot and cannot get both motors to turn at once. Each motor works individually if I upload a sketch running just 1 motor. I am using a onesheeld to interface via bluetooth and when I activate it, only motor 1 spins.
To narrow down the problem, can you remove the 1Sheeld shield from your system and see if the dual VNH5019 shield works with your Arduino by running the Demo.ino example program from our Dual VNH5019 Motor Driver Shield Arduino library?