Sometimes those connectors are changed so a more powerful fan can't be connected to a socket that can't power them. Check the Watts, or Amperage of the fans and what is usually connected to your source.
After that.
3 wire fans have + GRD and RPM wires. 12V. is usually Red, or Yellow, GRD usually Black.
4 wire fans add a PWM wire to control speed. Usually blue.
Some 3 wire fans have a thermal control that raises speed based on the temperature of the air passing through them. They must be used as exhaust fans to work properly.