If you hadn't changed any wiring when doing the replacement then I would go to the battery. Clean the terminals and ensure its a good battery before messing with any wires. I had similar problems with mine, thought it was ground, then the switch, blah blah blah. It turned out the battery terminals, although to the naked eye looked clean, needed a cleaning. That fixed it temporarily. Then the problem started again and it was the battery itself that needed replacing.
