looking for a radio wiring diagram for a 1991 mazda b2200, could anyone help???

Dude,
you don't need a wiring diagram.
Go to Best Buy or Circut City and they have wiring harness that will plug right in to your factory wiring and will wire up directly to any aftermarket radio that has been built today.
Or in the alternative, theyy also have wiring harness's that will plug right into the factory harness and then have color coded wires on the other end that explains what each wire goes to. (i.e. purple to left front speaker; grey to left rear speaker, etc.)