HTU21D Humidity Sensor Hookup Guide
This Tutorial is Retired!
The HTU21D has been retired from the SparkFun catalog. We recommend looking at the Si7021 which is a drop in replacement for the HTU21D.
View the updated tutorial: Si7021 Humidity and Temperature Sensor Hookup Guide
Contributors:
Nate
Nate 
Disabling I2C Resistors
There are two 4.7k resistors on the breakout board that pull-up the SDA and SCL lines. If you've got other devices on the I2C bus you may need to disable the on-board resistors. To do this you need to clear the solder jumper on the board. This will disconnect the resistors from VCC and from the I2C bus.