Newbie..picking up where my ex left off on my Datsun 1983 810 Maxima Wagon project. The headlights, turn signals, a/c won't turn on. I changed all the square colored fuses and bought a new Nissan battery.. and the alternator was changed over a year ago .. . Would this be a relay issue or fusible links? There are two blue plastic boxes I found near the battery..they look corroded inside ..I want to order the part online ..I couldn't find any factory part info ..any suggestions..thanks for your help