Your most cost-effective way to get this repaired would be to remove the stereo and take it into a local automotive stereo repair facility. If you can’t find one by looking through the phone book, call around too the dealer or almost any automotive repair shop and they should be able to tell you who are locally found in your area.
Just be ready for the diagnosis; a lot of time’s factory automotive audio systems are considered throw away when they start to give trouble; the cost of repair at times is more then a good quality after market system.
Dan.
Canadian "EH"