What if no image after installation?

Will IR lights on the camera be lighted on after covering the sensor by using opaque stuff like black cloth and etc? 1) If yes, it means the camera is powered successfully. 2) If not, please check whether it is the polarity issue( positive and negative of the camera is connected reversely?) Also, please check whether it is the PWM issue? if yes, you could try Haloview power booster BST2.