Most MGBs are wired for five-terminal alternators. As the five-terminal alternator is N.L.A., the current three-terminal alternal must be substituted. These wiring instructions supplied by Lucas outline the conversion procedure. To wire a three-terminal alternator, use plug # GEU250 and proceed as follows: • Disconnect Battery. • Cut off wiring terminal plugs from alternator wiring. • Remove and discard link wire. • Remove one inch harness tape. • Slide small insulator over remaining IND wire (brown/yellow) and solder to the small terminal. • The brown and black wires are not used, tape them separately back to the harness. • Connect the small brown/yellow IND wire to the small terminal on the alternator. • Connect the brown/white [positive wire to either of the large terminals. • Reconnect the battery.