I also think it's a noise issue because the dim/bright works (or sometimes works). The dim/bright is a repeating signal. That means that if you hold it down it continues to send a stream without the unit (and other stuff) so it can sometimes get thru. I've noticed that when the treadmill is running (my noise problem) I can get a dim/bright to usually work as long as I've sent a previous command to that light before the treadmill is fired up. It's the nature of the bright/dim X-10 signal.