Hi,
If you disconnect the IN from the arduino output and connect IN to Vcc then gnd, does the relay make a noise, does the light work?
Have you got a DMM?
With the controller reconnected can you measure the voltage from Vcc to gnd on the relay, when you activate it and deactivated it.
Then measure the voltage from IN to gnd on the relay, when you activate it and deacivate it.
Thanks.. Tom... 