This Preliminary Information communication provides information to the technician about vehicles that the Navigation radio does not have a global positioning system location but OnStar is able to accurately locate the vehicle. Technician should check the installation of the COAX cables to be router correctly. Technician will gain access to the Radio or Human Machine Interface depending on the vehicle build. Install the EL-50334 test antenna to the Radio HMI and evaluate the operation. If the GPS signal is restored, inspect for incorrect coax routing as described above and if found, reroute the cable so it does not bypass the splitter.