Make sure there is no power to the ceiling fan by turning off the wall switch that controls it. Unfasten the screws holding the base plate onto the fan, remove the base plate and then reinstall the screws just enough to hold them in the fan.
Locate the white wire attached to the light fixture. Strip one inch of insulation from the end of the wire and connect it to the existing white wire inside of the fan housing using wire nuts and securing with electrical tape.
Locate the hot wire attached to the new light fixture. This wire may be blue, red or black. If you are unsure, consult the manufacturer's wiring diagram. Strip the insulation one inch from the end of the wire and connect it to the appropriate wire in the fan. The configuration varies, depending on the fan model, so consult the manufacturer's instructions regarding the wire attachment.
Secure the housing to the screws that were previously used to secure the fan base. Tighten the screws completely.
Install the bulbs in the light fixture sockets and turn on the wall switch to check the lights and fan for proper operation.