Most MGBs are wired for five-terminal alternators. As the five-terminal alternator is N.L.A., the current three-terminal alternator 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.