Help finding short in dash/taillights?

My son has an 91 Acura Integra and the dash and tail lights keep blowing the fuse. He just got the car and everything has been working great until the last couple days. I asked him if he had done changed/added anything electrical and he hasn't. The tail and dash lights are the only two things on this fuse. Is there a way to isolate on or the other to see where the problem is?

Any help appreciated.

Thanks,
Bobg