There is a thread on this topic, I think I started it with the same question. Just a few inches fwd of that hot point is a floor bolt used for grounding, in vicinity of the center bolts for the 2nd row seat.
thats like I just found the 04 CV Interceptor modifiers guide where theres supposed to be a standard of a horn ring setup to activate your airhorns or sirens and its not. there should be 4 connectors i have 3 and then theres a split wire coming off 1 hookup that i cant identify cause i dont have a Specific wiring guide as to what goes to what off the connectors, but they cut 1 of those wires and spliced it back together but WHAT HE HECK IS IT!!! Does anyone have the wiring guide for 04 CV's out there??