The only fuse from the factory would be the amplifier fuse, if applicable. It may have another somewhere but that will have to be investigated further. Any way to talk to the previous owner? Any papers left in vehicle on the srereo? May need to see an audio tech! ....Could be just a unit installed to look like it has a stereo and the owner took the high dollar one out before sale?? Just a thought,
Best Buy, check their prices on a stereo,, installed. Check online for audio shop in your zip. Crutchfields can give you the best equipment at a super good price plus anything needed for the install but you need a car nut to help! Just some suggestions. Google Crutchfields. That's where we get all of our audio equip. at the shop for custom installition. Great place to deal with! You may already know.