Interference on theaux input

[newX3user]

Hi! Thanks to the help of the many people in this forum, I have finally finished installing a Garmin 360 GPS in the storage bin on the console. I got one of those flashlight adapters and Aux input connectors. I routed all the cables into the glove box through the console. Everything is working fine, except for the fact that whenever the gps is charging through the flaslight-to-cigarette lighter adapter I hear this static noise through the aux output.

Is there any way to stop this? When the unit is on battery there is no noise. So, I think it is the interference from the cigarette lighter charger. I thought those things were grounded to the car.

Thnka you.