Hi all...so perhaps it is my blondness but I could figure out how to create a new post...so here we we with my question and I apologize if this is not the right place. I have a 2008 Hummer H2 and my teenage boys recently put in a very awesome Train Horn. However, since then, every once and a while I get a notification that says, SERVICE BATTERY CHARGING SYSTEM and the battery light comes on. I have been doing some research and not sure I have a Battery Current Sensor on this vehicle. But from what I found is if the train horn is grounded to the Neg. battery terminal, which it is, it can cause the battery sensor to do all sorts of crazy things like giving me that error code. When I brought it to Auto Zone they said it was experiencing a parasitic drain but every thing regarding the battery charging system appeared to be fine. Any thoughts? Thank you in advance.