Last winter I parked my car 1983 Rx-7 in the garage. About a month later I wanted to open the back hatch but the battery was dead. I removed the positive cable and charged the battery. Fully charged I went to attach the cable and it sparked. I went through all the fuses, still it sparked. A mechanic suggested I remove the cable to the alternator then check for a spark, because it may be the alternator is bad. That worked, so I took it to have it rebuilt. The shop tested the alternator and said nothing was wrong. Any suggestions?

 

Sparking is normal when connecting a terminal...all it takes is one circuit to be active...whether its the dome light, or the key is in the on position, hazard lights...whatever, you didnt mention whether you were sure all those circuits were inactive.

 

I decided to see if I might find what could be on in the car. I hooked up the ground post, immediately the black main link on the fusible link lit up. I was to late, it fried. That leads me back to the alternator. One or more of the brushes must be bad, but not bad enough that it won't still charge. Any thoughts, I sure could use a little help.

 

Have you tried hooking an inductive ammeter to the battery cable to see if its discharging when you think it shouldn't be first?