Car HUD Head Up Display, Universal KMH & MPH Digital GPS Smart Speedometer with Suction cup holder OverSpeed Alarm Fatigue Driving Warning USB Interface for All Vehicle

•The screen without any display, and no powerCheck whether the USB cable is damaged, replace the USB cable for testing, and prohibit the use of voltage higher than 5V for power supply.

•Without car SpeedAfter HUD power-on, the satellite icon flashes will start to find the satellite. Please driving the car to the road. It will work after it stops flashing.

•1. Inaccurate Speeda.First check the speed unit is correct or not, the speed unit including KM/H and MPH, please refer to the setting to switch the unit.

•2. Inaccurate Speedb.The car manufacturers usually make the dashboard speed 5-7% higher than the ECU. The international standard is based on satellite data.(if the dashboard shows 100, and the device shows the 105, change the default value at 102)

•Driving direction display errorAfter the vehicle speed exceeds 5KM / H, the direction can be displayed normally.