2003 Stratus Vacuum leak

I bought a used Stratus for my daughter around Christmas. When I bought it, the check engine light was on, but I found that it was a vacuum leak before I signed the check. I have tried everything I know to find the leak, but can't seem to isolate it. Does anyone here know where the vacuum line that disappears into the front near the passenger side headlight terminates on the hidden end? Has anyone had a problem with vacuum leaks? This one is not bad enough to cause the engine to run ragged, but I would like to turn that dang light off, and I am certain that we would pick up a bit of mileage without the leak.