pull the cover off the fusible link box just forward of the battery. If they are smoked you usually have a visual indication. Be sure there is a feed from the +12 battery post to the fusiable link box. If you pull them out you can check with vom. look for corroded broken burnt connectors in the box. location shown in the fsm on EL191 (that is 85 but probably there or close by). be sure battery cables are clean and free of corrosion both ends and terminals are tight. Have the battery load tested. Z's with low voltage are a gemlins paradise.