Thanks natster! I'm positive now that we indeed do not have one! We ended up just disconnecting everything. I was going to just disconnect the negative end but after having a spark from the wheelchair lift thingy we decided to disconnect everything.
Now I'm trying to figure out the whole wheelchair lift thing that's by the batteries. The previous owner removed the actual lift but something is still being connected to the batteries. Here's where it connects to the batteries.
I followed the wire the best I could from the batteries, and found that it led to either here:
I am pretty sure that it's the first one, as it's in the same casing as the wire I was following before I lost sight of it above the gas tank. I know I am not the smartest when it comes to electrical, as my gpa proves after a year of physics, BUT I don't understand why it would lead to here? It looks like it's just a ground but that makes no sense as it should have been what was powering the previous wheelchair lift.
Does anyone have any experience/knowledge/advice???