first i would like to say that i dont know every thing about the z,s im not familuar with yours, but i race the 280,s and the one i have was found in a field so it had every problem you can think of. i had this prob. w/mine. close to the battery there should be a small box with fusable links these are a prob.in the z,s. if your car has this box it is easy to test. the wires in this box are eithier burnt or corroded. your dash lights probably dont work or your tail lights dont work either. if this is true if you get charging prob. fixed it will fix the other probs. O.Kreplace the wires in the box with new ones. I recomend one size larger than stock. THIS IS BASED ON THE PROB. I HAD WITH MY 1980 280 zx.