Unfortunately there isn't much you can do on the road to correct this condition. There are two possibilities. One is the screen/radio failing but more commonly it is an issue with the software.
There have been issues with black screens on your vehicle with nav radios and there is a software update that should correct it.
It would be necessary to visit a dealer to correct this.
The nav disc is removed and a software update dvd is installed temporarily that reprograms the nav radio.
#08-08-44-013E: Navigation Radio Intermittent Blank/Black Screen, Map Disc Read Errors, Features Not Accessible While Driving, Navigation Radio Resets Upon Startup (Update Navigation Radio Software) - (Jul 27, 2009)
This bulletin is being revised to remove the NAV Disc Center Website information. Please discard Corporate Bulletin Number 08-08-44-013D (Section 08 -- Body and Accessories).
Note: If the vehicle has a 2008 MY radio and the software version is 100M or higher (e.g. 100N) for the SuperNav navigation system (Escalades) or 100F or higher (e.g. 100G) for the BlackTie navigation systems (Lucerne, Enclave, Equinox, Acadia, Torrent, Outlook, and VUE), the improvements/corrections offered via update disc 20774148 are already installed and this update is not required. The screen will display the following message "The disc installed is not a MAP DVD".
THIS IS NOT AN ERROR MESSAGE.
Customers may comment on any of the following conditions:
These conditions may be caused by software anomalies.
Don't Do This
Update the Navigation Radio software.
Do not replace the Navigation Radio.
Technicians are to update the Navigation Radio software using a software update disc, P/N 20774148. The software update disc is to be obtained from the GM Navigation Disc Center, using the contact information below. Follow one of the two procedures below as appropriate for the vehicle you are working on.
Note: If the radio has software calibration 100M (2008 MY radios or earlier) or higher (e.g. 100N, etc.), the software corrections contained on the update disc 20774148 are already installed and this update is not required. The screen will display the following message "The disc installed is not a MAP DVD". THIS IS NOT AN ERROR MESSAGE. To verify the software version follow steps 1 and 2 below.
Important: For the condition regarding features not accessible while driving, this will only be addressed in 2007 and 2008 model year Cadillac Escalade vehicles.
Important: Do not turn off the power or remove the update disc while the software update is in progress.
Important: This software update procedure will erase the customer's Address and Destination entries from memory.
Note: If the radio has software calibration 100F (2008 MY radios or earlier) or higher (e.g. 100G, etc.), the software corrections contained on the update disc 20774148 are already installed and this update is not required. The screen will display the following message "The disc installed is not a MAP DVD" THIS IS NOT AN ERROR MESSAGE. To verify the software version follow step 1 and 2 below.
Navigation Radio Software Update Disc
Ver. 100M for SuperNav radios 08 MY or older
Ver. 100F for BlackTie radios 08 MY or older
Navigation software update discs are for the dealer to update the Navigation Radio software only. They DO NOT update or replace the navigation map disc that is supplied with the vehicle. Please order these parts only as needed. There is a limited supply of these discs available. Do not order these discs for stock. Do not give the software update disc to the customer. Navigation software discs may be used to reprogram more than one vehicle. The first update disc for each P/N is free. Subsequent copies of the same P/N for the same dealer will cost $50 (USD). Refer to Corporate Bulletin Number 06-08-44-012C for additional information on how to obtain AVN software update discs.
GM Navigation Disc Center Contact Information
Note: Navigation Radio Software Update Discs are no longer available via the Web. They can only be ordered by calling the following phone number:
GM Navigation Disc Center at 1-877-NAV-DISC (1-877-628-3472)