Yup, Electric gremlins are a BEOTCH!...you havent stated the condition of your wirin harness NEW/OLD..you are lookin at SO MANY "IFS" right now that any decent interpretation will be almost impossible.
I would as stated above ...start at the last point of entry ..
seems like you disturbed something that was cool for a long time till you moved it.
NOW you have a gremlin ..wich if you just use common sence can be found NP.
I would personally start with a freind in the dark, he/she watches as you push an pull on the wires at the battery an work from there an look for a spark.
NO LUCK?? time for the meter an start searchin wires ...you have a short/bad ground goin on somewhere.
Tim
