Nissan Repair: dim headlights, headlight switch, core support

Question
I have a 96 Nissan Pick up and headlights are ALWAYS very dim, I have checked the battery and alternator and not sure where the ground is supposed to be so I'm not sure how to check that or how to go about fixing the very dim headlights. They are dim regardless of which setting they are on.

Answer
Matt,

It is probably the headlight switch that is causing the problem.  The contacts get old and it causes the lights to dim.  Also, unless the vehicle as been in a front end accident the grounds usually never screw up.  They are located at the front of the vehicle on the core support.