if it is a big power wire ( same size as the battery cable ) then it is the earth wire you should find that the battery has one wire going directly on to the engine or chassis
there are different arangements the negative wire could be coming directly to the starter and if this is the case then the wire is just earthing the engine but in a lot of cases the starter is getting its ground from the engine and the engine gets its ground from the battery
The starter on a 1995 Nissan Pathfinder SE V6 is located on the bottom, left side of the engine. It is mounted in place using a series of bolts and a mounting bracket.
The 2005 Nissan Pathfinder has a V6 engine.
The 2003 Nissan Pathfinder has a V6 engine.
The starter is located at the passenger side below the engine exhaust manifold facing the flywheel parallel to the transmission.
The 2002 Nissan Pathfinder has a V6 engine.
Inside the right of the engine compartment, near the battery.
The 1995 Nissan truck starter relay switch is located in the fuse box. The starter relay switch will be in the third column.
The 2001 Nissan Pathfinder has a 3.5 L base engine size.
The 2004 Nissan Pathfinder has a V6 engine.
The 2011 Nissan Pathfinder has a V6 engine.
The 2012 Nissan Pathfinder has a V6 engine.
The 2001 Nissan Pathfinder has a V6 engine.