Is it a good practice to auto "switch-on" a setting based on a dialog confirmation?

Imagine that as a user, you can use an app to start the A/C of your vehicle remotely. To do that you just simply need to open the app, tap on "A/C" and then press start. But if the car is not plugged-in (electric powerwall), the function requires that you activate a certain setting to confirm that you allow the vehicle to use battery power.

Which is the best workaround?

A) When the user Press start A/C a dialog will ask to activate the setting, after taping activate, the setting will be automatically activated and the A/C process will start.

B) When the user Press start A/C a dialog will ask to activate the setting, after taping activate, settings screen will be displayed and the user will have to manually activate the setting.

All the feedback will be welcomed :)