If you're referring to the ground connection that goes to the engine block, it's easily accessed from beneath.

If your cable arrangement is like mine, the OE passenger side negative is a single cable connected first to the inner fender and then to the engine block. I changed to two cables from the battery (-) - one to the inner fender and the other to the engine block. There is also a negative cable on the driver side from the inner fender to the engine block, also accessible from underneath.

The fender connections should be easily accessible from above with a step stool.

Frank