what year's your car, and do you know if lincoln offered a factory-installed cd changer as an option? If it was made in the last 10 years I would assume so, since a lincoln is a luxury brand. If there was a cd changer, then your head unit either auxiliary(RCA) inputs or a spot where the OEM changer plugs in at. You can find adapters that plug into that spot and give you RCA-ins
here, but I know I've seen them cheaper. This has been discussed a zillion times, so I'm sure you can find a link to a cheaper source if you

the forums. You can then buy an
adaptor cord that goes from headphone jack to RCA, and you're all set.