elctrical problem?

the vehicle won't turn over unless the head lights are turned on.  not every time does it do this.  I have interior lights and the dashboard lights come on but go dim when the key is turned.  Also the vehicle will shut off while in drive, almost like the fuel pump is not supplying any gas.  what could this be?

 Try checking your ground circuits. Had a similiar problem years ago,seems that was the fix.