Turn by turn navigation on iphone 4s not working when phone is charging

[chikntender]

Basically my Maps app on my iPhone 4S (with the latest iOS update) will not give turn-by-turn voice navigation if my phone is plugged into the USB charger on my car. I recently started a job which requires a lot of driving and I would really love to get the voice navigation working. My phone is older and the battery drains very quickly so it's necessary that it be plugged in during my trips to charge.

The voice navigation works fine when my phone is not plugged in. Are there any work arounds for this issue?

 

[Applejuiced]

So the wire its plugged into a usb port on your car?
Try using a different charger, one with a cigaret adapter plug. Sounds like when its plugged into your car it might try to pass the sound/navigation directions through the cars stereo system instead and disables the iphone speaker.

 

[chikntender]

Yes, I plug it into the USB port in my car. Unfortunately I can't use the cigarette adapter for this. I work a food delivery job so I have a hot bag that needs to be plugged into the cigarette adapter. I see what you mean about it possibly trying to go through the car speakers when it's plugged in though. Do you think plugging it into the aux jack would be an option?

 

[Applejuiced]

Not sure if it will work but give it a try.
They also sell those cigaret adapter plugs that split 1 charger port into 2 plugs.
So you can both charge your phone and have the pizza sign still plugged in.