where is your ground cable located in your engine bay. the ground cable that is used for the power output for the sound system

 

if you are running an amp, you can connect the ground cable to any ground location near the amp. try to keep the cable leangth under 2ft. you dont have to tap into the battery ground. there are plenty of ground locations under the seats if you pull the carpet up, or in the hatch area under the spare tire / storage area.

 

Never run your amp ground back to the battery ground or you will create a ground loop. Choose a spot near the amp, scrape the metal so that no paint reamins. You need to use a spot with bare metal for the best contact. Use a self tapping screw and a star washer (for best contact again) and tighten it down.