Why cant I find a GPS signal?

The reason you may not be finding a GPS signal could be any one of these :

-Poor Weather

-Undergound/In Tunnel/In Garage

-Software is out of date

-Device is broken

The list of reasons above is ascending in order of seriousness. Poor weather can be waited out, Being underground/in tunnel/ or in a garage can be fixed easily by leaving that area, Software can be updated, however, if it is the device itself you will need to replace the entire motherboard because the GPS locator is not a peripheral device. Guides to do this are on this page

TomTom VIA 1605TM