While lubing the drive train on my 05 i noticed a leak on the passenger side just behind the wheel well. It appears to be green like typical coolant. It look like it is for one of the rear heater lines that runs down the passenger side. Question is the coolant in the truck is red and this is green. I looked and searched but could not find the answer if the heater runs off its own coolant? If so where is the fill? Or if anyone has a different idea on what it could be. It is on the outside line of two lines that run parallel to each other that are covered in a protective foam.