Not your typical lighting question

I was able to successfully tap into the dome light circuit and use a constant power source for home made puddle lights on my Tacoma. Now the question, on a 2015 Camry doing the same wiring the lights remain on just very dim and not all the time. I know LED's require less power to operate but that doesn't explain why it's intermittent. Toyota has a kit for puddle/courtesy lights with LED's for the Camry. What do I need to look for or solder in to kill the power as soon as the interior lights go out?