2004 Dodge Intrepid Phantom battery drain?

Several months ago I had a license plate light wire repaired. 4 days later the battery drain started. It has happened 3 times since the garage repaired the wire. The car will run fine and upon sitting 4 hours, or a week, the battery is completely dead. The garage that is working on it now states that it can't be draining the battery because of that light repair? What do you thinik? I am a lady driver and need some advice. This complete drain is random.