Posting this in case it helps someone with the same problem I had. I installed several sets of LED puck lights under my kitchen cabinets and they worked fine for about a month before they began to flicker and even fade. This happened independently (and not at the same time) to all 4 sets and had me puzzled for a while. These were sets purchased from Home Depot that had a switch (on the DC side of the transformer) and their own transformer which I had put into a junction box. I just left the switch on because I was using the wall switch to turn them on and off. It turns out that the switches that come with these lights are awful. When I opened up the junction boxes I discovered that when I held the switch hard in the on position the lights would be brighter and not flicker. So I merely cut out the switches and spliced the 12V wires together. Problem solved and a lot less stuff in the junction boxes!

Sorry to be catty but be wary when taking advice from certain users. Refer to this thread as an example: "o Hardwire a chandelier". I am tired of seeing advice which is given as authoritative when it is wrong. Dimming from more than one location is simply a matter of preference in most cases but also of convenience. Texasredhead, if a light is turned to a dim glow where one can barely see should one have to walk across a room to find a dimmer to turn it up if there is a dimmer closer by? Dimming from more than one location is possible. Any reputable electrician would know that. The dimmers communicate with one another through leads on the dimmers which are linked together through the switch wiring. Tklahr, try different brands of bulbs rather than just different types. Also look for bulbs which have filament supports. Many bulbs simply have a filament stretched between two arms with nothing else and that lends itself to vibration. As for flickering, if the wiring is all sound it may be an issue of a heavy load somewhere in your home causing the flickering.

This exact same thing is happening at my house, as i type! I am in the living room, this room's wiring is not affected but the kitchen is flickering and going off and on like crazy...wind is blowing outside and hubby has discovered it has something to do with electrical pole across the road. we called electric company and they came out and checked where the wiring is attached to the house, no flickering there...but when hubby goes out and shakes their pole...all hell breaks loose! When they came to check the pole, the guy didn't even go up there, and told my husband to stop shaking the pole...yet nothing has been done to fix this...guess he will be calling them today and stirring up a stink...i believe this on / off crap could damage our appliances and such. Funny, nothing flickered last night during storm with 50 plus mph winds...go figure....

Eliminate half the possibilities, get a good extension cord and connect the lights to that. If the flickering goes away it is the plug if not then it is in the lighting. If it is the plug turn off the circuit at the breaker panel until it is repaired because it is a fire hazard. Connect another lamp at the first puck and power up, if it flickers it is the cord, if not it is in the puck. It is possible you have a fuse in the cord,not sure, just a guess.