just in that general area, i need a big enough one to handle 1/0 wire, i sanded down a spot under the rear trim panel and drilled a nice hole...should work for now but would like a better one. I have a secondary battery so i have to have 2 grounds and 2 power wires ran, secondary battery to ground, amp ground to Other ground(still need to find one), front battery positive to rear positive, rear positive to amp positive.were about's..... on the rear passenger side there is a ground for the inersha pressure switch and on the driver side there is the radio ground. you got to pull back the truck liner to get to them. behind the wheel wells in between the rear bumper and the wheel on that side is were i am talking. i believe it is a nut with a 8 mm bolt head this is on the 1997 Taurus.