Bluetooth Button Press Default Change

I have a bluetooth headset I am using with a Galaxy S4, where a long press (longer than a quick press but less than 3 seconds) will trigger voice control. When I first tried to do this action it asked me to choose a default between google, and car mode. I accidentally selected car mode and now I can't find any settings which will let me adjust that. I've gone through every single menu in both applications, and the system settings. Is there some way for me to reset it, or change it by editing a config file? Thanks!