What can you do if you are the primary buyer and the co-buyer who has the car is not making the payments and you cannot locate the car in Florida?

I recommend discussing it with the LENDER. Ask for "help" in "locating" the car. If that doesnt work, contact a FL repo company for advice. NOTE. Is the TITLE in your name(owner OR co-owner)? If you are simply on the LOAN contract, you are in a mess.