Audi Repair Questions? Ask a Mechanic for Answers ASAP
DC systems do not use a neutral only a power and a ground. Go to any auto parts store and get yourself a test light. That would be the easiest way to find the power wire. You can hook them up both ways, the worst that can happen is the fans will spin backwards. You want them pushing air towards the engine.
Please reply to this if you need more help, then we can continue this conversation. If not, please rate at the top of the screen. Rating does not close out your question. Remember, sometimes it is difficult to completely diagnose your vehicle without being there, but I will try to give you the best answer I can. Remember, I do not get compensated for my time helping you unless you rate. Thanks Dan