FSS is a Mercedes "system". It is relatively easy to reset. If it really can't be reset by your Chrysler dealer, head over to your local Mercedes Dealer, there is one in La Jolla and one in San Diego and they should be able to reset it in the service drive as a courtesy to you. The Mercedes folks have been quite accommodating to me every time I pull up in Colorado or California with the Crossfire. The service people are very well educated and will tell you if you truly have a defective FSS system.
Good luck.