Did yo download the a voice?
From:
https://help.here.com/ios/maps/#q6291
How do I download a voice for navigation in HERE Maps?
Open the main menu and selectSettings > Guidance settings > Navigation voice.
Standard- and high-quality (hi-fi) male and female navigation voices are available to download in UK English, US English, French, German, Italian and Spanish. (The standard-quality UK English female voice is Included with HERE Maps when you install it.) All of the navigation voices in these six languages announce street names. The other navigation voices available in HERE Maps are standard-quality but don't announce street names. They will, however, tell you which way to turn and when.
If you download a map of a country or region and use drive navigation there, you won't automatically hear voice navigation in a language spoken in that country or region. Navigation voices and downloaded maps behave independently of each other.
You need to sign in to your HERE account to download hi-fi navigation voices.
You can also sign in to HERE using your Facebook account.
That that an iPod uses nearby wifi networks that are in Apple's database for location. You do not have to be connected to a network to use its location Thus, you may have problem with location.
You also said " The volume is up, Siri works,". To use Siri you have to be connected to the internet
