Double check and make sure the pigtail called for is the same. In theory they are because its only one model year difference, but manufacturers are notorious for making changes even in mid model year without warning.
But it really sounds to me like someone did some rewiring. Get a cheap 12 volt tester, the kind with a bulb in it. Test each connection at the 7 pin connector by having someone sit in the driver's seat and go through each light, brakes, signals, etc. That will tell you a lot and give you an idea on what to do.