Does the car have to be running to use the car charger for my cellphone?
NO. Just make sure there is power there, may have to put the key on Acc, but the draw is very low, it does not need to be running
it will not charge the cell phone unless the car is turned on- look at your charger light- when you shut the car off, the light on the charger shuts off too, so it is NOT charging if that light is off- most GM cars are like that.
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