Hello all! This should be a very basic question, but I'm just drawing a blank and haven't had a chance to do extensive testing to come to an answer on my own. Regarding 12v dumb RGB LED rectangular modules (http://www.holidaycoro.com/RGB-Rectangle-Module-p/56.htm), MUST they have the negative wire hooked to the negative output of a power supply, or can I simply ground the negative wire(s)? I think I'm confusing negative with ground - they aren't the same are they? I'm trying to wire up a short strand of these using just a positive 12V in and ground the Blue negative, but no light. I thought I could make them work similar to any automotive lighting works; +12V in, ground the black wire. I think I'm missing something very basic! In addition to the answer, could somebody please explain WHY it is and has to be the way that is needed? Thank you in advance!