Hi, new to all this but I've been working on getting a setup done for the TV in my living room. BUT I'm having a huge problem. When I connect the lights to my PSU nothing happens, the PSU is 5V 15A 75W output, the rpi 3 boots up just fine and has not undervoltage issues, I have used the gnd and 5v+ pads on the strip and have gotten a few leds to light up. Usually the one I'm touching the (+) wire to and the first 2 or 3 LEDs from the beginning of the strip. Can someone tell me what I should do? I feel like it's a simple fix (hopefully) and I've done electronics in cars before. But I can't see any results. Keep in my mind that if I connect the wires to the wire harness that came with the LEDs I don't get anything at all. Please can someone help me? Thank you in advance!
*Update* I've decided to runt he Rpi3 through its own power supply. Now I get 1 LED to consistently stay on, looks like a cyanish blue. But no other lights are coming on.