My truck has power but will not turnover

I drive a 1995 Dodge Ram. My truck started
missing when I was on my way home so I
replaced my spark plugs and wires. Started
fine the next day. The day after that it didn't
start very easily and wasn't running right and
died a few minutes after I started it. Then it
wouldn't start. I got a jump a few hours later
and it was running good but the check
engine light was on. I drove it around a bit
and shut it off for a few minutes then started
it backup and it was running fine. I started it
up Monday morning and noticed the battery
wasn't charging all the way so I shut it off
and started it again and it still wasn't
charging right. My positive terminal was a
little corroded so I took it apart and cleaned
it and now my truck will not turnover at all. I
had the starter tested. It's fine. Got my
battery tested and it was bad so I put a new
one in and still nothing. I just noticed that my
headlights do not come on when I pull the
switch. There is power to everything else
and I can hear the fuel pump kick on when I
turn the key it just will not crank over. Does
anyone have any suggestions on what it
might be? Any help would be very much
appreciated