1985 300zx non-turbo has elec. problems

[bdm62]

i am having trouble w/ the elec. system-battery is charged, alt. is charging right, after replacing 3 times since last nov, but, elec. system goes totally dead for no reason at all. car will start and run fine, over and over, then, out of the blue, NOTHING! even the dome light wont work when i open the door. put jumper cables on, and it fires right up! could it be the fusible link, somehow? that is all i can figure, since it seems as tho the battery is dis-connected, until i jump it. anything else, wouldnt the dome light work? i am at a loss, and my g/f thinks i must be stupid! also, how do you replace the middle spark plug, on the left hand side? THIS is really pissing me off!
Modified by bdm62 at 8:35 PM 4/14/2007

[evildky]

most likely the voltage regulator which I believe is internal on your alternator, you can take it out or drive teh car or atuozone and they can test it on the car or on the bench, most likely you'll have to replace the whole alternator, this happens to many vehicles