I have a couple lamplincs and all of them are still applying power to the connected LED bulb when the lamplinc is turned ofd. The bulb is a standard c7 base night light and is .5 watts. I could switch to an ON/OFF module but since I have so many extra lamplincs I put them to use. It this behavior typical for such a low wattage LED? 

Yes. Both the old 2456D and present 2457D2 LampLinc modules have local control sensing. This small sensing voltage is enough to keep low power LEDs glowing when Off. The older 2456S ApplianceLinc also has the sensing current and will cause low wattage LEDs to glow. The 2635-222 On/Off modules don't have the sensing voltage and don't cause a low wattage LED to glow.

The LampLinc manuals indicate you can turn On and Off local control sensing. I have found the sensing voltage is still there when disabled. Just ignored if you toggle the lamps local switch from on to off and back on.

Found differences in the 2457D and 2457D2 manuals. Some of the older revisions did not have sensing. So I can't say if the small voltage is on the older revisions.

 

Edited March 30, 20196 yr by Brian H
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The lamplibc is rated for a minimum 5watts so that may play a part as well

1. If you have an old phone charger and can plug it in with the light, that might help, if the problem is what @lilyoyo described. Very likely the problem.
    
2. Also, being able to turn on, but not off, is sign that the load is introducing line noise and the Insteon "off" message is not getting through . I've had cases where line noise even overwhelmed the switches ability function with RF. You can test this by temporarily trying a different load and seeing what happens.

Paul