Electrical Short & Battery Drain
 

I'm having two problems that may/may not be related to the same thing. first of any time i use my rear defogger my radio cuts off and doesnt come back on until i turn the defogger off. second my battery is being drained by something because i started my car last night (started fine) and went to start this morning and it was dead. so idk ive changed a battery, terminals (which still act up from time to time) and need help on what to do from here.