Why is the ford flex sync not working?

When the Sync system is not working in Your Ford Flex the first thing that You should do is try to restart it. Often a simple reboot will clear up any software problems that could have made it freeze and not work properly. If resetting it does not work, or it was never on in the first place the next thing that You should check are the fuses to it. You will want to make sure that these are in tact, and replace them if they are blown. The last thing You should check is the wire harness at the back of the radio. If this is loose or has frayed wires then that could prevent it from turning on as well.