First of all, make sure you have the screen brightness (on the dash, left of the instrument cluster) turned up. I've made the mistake of bumping that and thinking my display wasn't working before, it's easy to do.
Otherwise, if the screen goes blank, turn the car off and then back on. Always fixes it for me. Sometimes if you unplug the USB, plug in the USB, etc. it comes back, but sometimes nothing except a power cycle will fix it. Annoying, but fortunately nothing mission critical relies on the flaky center screen...the instrument cluster is rock solid, as it is a safety critical system and as a result is a much more robust design.
Bryce