This is what I would do given the information! Some wiring in cars do not hook directly into aftermarket stareos. Check with a spair speaker to see if your deck is working. If it is, then the problem is in the wiring to the car and you mmost likely need another adapter. If you had sound before the spark, then it is most likely your amp. In this case, include an amp into your sstereo configuration and problem solved.
note, some car audio has power amps built in and can have blown/burnt fuse due to the spark, however unlikelydon't forget about that