RBACK.
I have edited my last post due to my mistake. Have a read. Like above, yours may be stuck on rather than off. Check the box, as it is relatively easy to pull out with out disconecting it and you may get a better read on whether it is the problem or not. I disconnected the battery before messing around with the boxes to avoid a possible ground out. Call me anal, but better safe than sorry. Let me know how you make out.