NAVLINK NO GPS SIGNALand sometimes shows grey signal strength which means not strong enough to receive, help needed to fix this problem. tthanks

Happened to me recently,  showing grey signal bars but never locked (turn blue) so I was quite frustrated by it as I've only used the system a few times.  I have chased up a few suggestions from the web & the one I tried work.   Some suggested using Sirfdemo to reset the GPS receiver to NMEA mode as they could accidentally go into SIRF mode if the device is left active but has no view of the sky for an extended period (can easily happen if you left the unit in standby mode and placed the GPS in the glovebox).   The other solution is to remove the battery for anywhere from 24 hours to 7 days so that the SiRF chip capacitor will reset itself ...this is the solution I tried -  I left my unit without the battery for about 5 to 6 days and it came back to life again,  I've read some people left their GPS (albeit not Navlink) off for 4 days but still didn't work but retried again for 7 days and it worked.  Remember, once you place the battery back in I think the capacitor is charged up again so if it was not left off long enough you'll have to start counting from day 1 again.   All the best.  Jono