Hi I have installed a small run of LEDs but they do not work at all unless I reverse the connection that goes directly on to the stip so that it's not lining up with 12v symbol. I tested everything before cutting the strip to length and it worked fine but now it will not switch on with remote. I have changed the controller and remote with different ones but still no go. I would be very greatful for any help. Thanks
Look very closely on the cut LED strips and make sure you did not short the + and - sides to each other somewhere, such as where you cut it... if the strip is shorted, the power supply will sense that and shut it down.
Also keep in mind, polarity matters on LEDs - if you hook the wires to the strip backwards, it will refuse to light. Won't do it any damage, just reverse polarity and it should light.