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Used to turn it back on...appears now that its all under Privacy and it appears to stay on even if Airplane mode is on.
Are you talking about Location Services? I'm not sure that controls just the GPS directly/specifically.
 
Assuming you meant you turned data off as in no connection at all the route is preloaded. If you were to travel off the route (even just stopping for food or gas) and it tried to reroute it would fail.

Once the route is loaded it's relying on GPS so a internet data connection is not required.

Don't tell em....let them figure it out. The post where starting to get comical
 
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