Navigation doesn't start with Siri Eyes Free

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This seems to be an issue when Siri thinks you are pressing a button to activate her she thinks you are looking at the screen (which is not the case). If your iPhone is connected to a power source in your vehicle, try the command "Hey Siri" to activate Siri (instead of pressing the button). This will force Siri to work on hands free mode. Hopefully a fix will be released in the future.

-Zeph

You are welcome, I hope all works out. Have a nice day!

-Zeph

I have this problem also. In my case it is with a JVC KD-X320BTS digital multimedia receiver just installed in my sons car to give him bluetooth hands and eyes free phone etc control. His phone is a new iphone 6 plus running IOS 8.3. In this system you activate Siri by holding down the phone button on the head unit. Everything works great, i.e. calling, messaging, music control etc. But as with the orginal poster, when you ask Siri for direction, the conversation goes fine and she says she is getting directions, but if the Maps app is NOT already open on the phone, nothing happens. If the Maps app is already open, everything works as expected. In this system I think the suggested "Hey Siri" workaround will not work, because I think that the microphone is not active until you hold down the phone button, which must be doing something equivalent to holding down the home button.

This behavior is the same whether the phone is untethered, or it is plugged into the USB port on the head unit (where it uses usb for music audio, but BT for phone and voice control).

So, yes this sounds like a IOS software bug to me.