oh.sick.silverado

So i recently lifted my 2006 silverado 1500. it’s a 5.3 regular cab short bed 4x4 with the basic interior (rubber floors, floor shifter). I recently lifted the truck on 35’s and tried to tune the truck so my speedometer was accurate. I have a flashpaq 2865. it works fine on my dads truck, a 2008 gmc sierra denali, and turns on as soon as i plug it in. the tuning functions work as it should. i plugged it into my silverado, and it wouldn’t even turn on. i can’t find anything on youtube or google about this, and my code reader works fine and turns on without any problems. i just can’t seem to get power to the flashpaq. anyone else having similar issues?