Headlight

I have a 2001 Mazda Tribute ES.  My one Headlight is dimmer than the other and the highbeam does not work.  I changed the headlight/bulb which did not work and then I changed the connector that plugs into the headlight/bulb and still the same issue of the headlight being dimmer than the other and no highbeam.  Any suggestions?  Could it be the wiring?

I am going to assume here you already tried replacing the headlamp bulb.
 
Next I would suggest the wiring, more specifically the plug.  The dim light sounds like a ground issue.  The bright not working sould be a short in the wire for the bright. 
 
I just had to replace the plug on one of the headlights for my '02 Tribute.  It cost $10 for a pair of aftermarket plugs at the auto parts store and 3 wire crimps to install.  Make sure you connect it right, the wire colors on mine didn't match the factory wiring (not that you would expect it to anyway).

I have a headlight socket problem (melted / corroded) with my '03 Tribute, is the replacement socket a common item in most auto parts stores?
 
Thanks