You own a 1999 Daewoo Nubira and have had the Alternator changed recently Ever since replacing it you still lose all power and the Alternator is in good working condition Any ideas on what this could?

Answer 1

I would start with a voltage drop test on both be positive and negative side of the battery. I once had a Corvette in the shop that three other shops couldn't fix by replacing the alternator with a high output alternator. The car ran fine all day long with the air conditioning on, but when driving after dark with the air conditioning on the battery would inevitably go dead. This was a late 60s early 70s Corvette stingray with the battery mounted behind the driver's seat. The negative cable ran through a rubber grommet in the floor of the fiberglass body and bolted to the frame of the Corvette. By doing a voltage drop test on the negative side of the battery cable from the battery to the bolt on the frame I had about 3.5-4 volts of voltage drop if I remember correctly. The connections on both ends of the cable were clean, but where the cable went through the rubber grommet, the cable looked like it was pregnant. I removed the negative battery cable and inspected the bulging cable insulation and could see absolutely no nicks or wear marks on the cable insulation at all, yet when I cut the cable open in that area it was full of green corrosion. I replaced the negative battery cable (less than a $5 repair) and the customer never had any more problems from that point on, and we dealt with him for several years after that.