'03 model

Remove the center console (see CENTER CONSOLE REMOVAL/INSTALLATION ).
Disconnect the 6P connector (A) from the seat heater switch (B), and remove the switch.

Fig 1: Disconnecting 6P Connector From Seat Heater Switch
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Check for continuity between the terminal in each switch position according to Fig 2 .

Fig 2: Checking Continuity Between Terminals In Each Switch Position Chart
Courtesy of AMERICAN HONDA MOTOR CO., INC.
If the continuity is not as specified, replace the illumination bulbs (C) or the switch.