On your display, select Maps and locate the navigation arrow. If the arrow is gray, power cycle the vehicle and move to an area with an unobstructed overhead view. Once the navigation arrow turns red, the display has acquired GPS signal. If problems persist, check connections on the GPS receiver on the display or see your dealer.
For the 7" Display specifically, determine how many satellites are connected. Select Main Menu > Vehicle Settings > GPS Status to see how many satellites are currently connected. If the status has less than four satellites shown, move to an area with an unobstructed overhead view. If problems persist, check connections on the GPS antenna on the display or see your dealer.