The most common reason for a non-working i-Socket Autoswitch is related to the actuation threshold (which is the minimum amount of current that the tool must draw in order to turn the ACCESSORY outlet on). The i-Socket Classic has an actuation threshold of about ~0.7 amps (roughly 85 watts) so there has to be at least this much current flowing to the tool before the ACCESSORY outlet will turn on.
Alternatively, the i-Socket Plus and i-Socket Workshop have lower actuation thresholds of ~0.5 amps (roughly 65 watts).
A simple way to test this would be to plug a power strip into the TOOL outlet and then plug in a light fixture or second tool in to the power strip. Run them at the same time so you are sure that the current draw is above ~0.7 amps. With them on at the same time, the ACCESSORY outlet should turn on.
If you have our WORKSHOP Autoswitch, the most common reason for a non-functioning unit is having the Mode Switch in the incorrect position. Make sure the Mode Switch is in the AUTO position, and the vacuum power is in the ON position. Please refer to our instructions for the proper mode position. Also, make sure your tool is drawing at least 65 watts. The i-Socket Workshop actuation threshold is ~.5 amps (roughly 65 watts). Refer to the paragraph above for testing.
If your WORKSHOP Autoswitch still does not function properly, contact Customer Service.