There are various methods useds, the main ones are:
- Eeprom ,this means opening the instrument cluster and clipping to the eeprom.
- Diagnostic OBD, this means connecting to the on board computer cable directly to the car.
- Dash Diag, this means you have to remove the cluster , but not open it. You can change it from the back of the dash.
- Micro, solder a few cables to the board.