I just purchased a 2012 Ford Focus. After reading about the problems disconnecting the battery. I found on the internet a Side Post Battery Master Switch (Part Nbr. BS100), made by GAMA Electronics, P.O. Box 1488, Crystal Lake, Il 60039, Phone 815-356-9600, Fax 815-359-9603. I removed the negative battery cable at the firewall and installed the switch inline. Had to bend the lug on the cable a little. Now I turn the konb 1/4 counter clock wise and the battery is disconnect and 1/4 turn the other way the battery is reconnected. Works find for me, They have a good video on line
