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Check, check, is this alternator/battery on?

Re; 2002 BMW 325Ci Convert. 5- sp Manual Trans.

2 weeks ago, while out of town, my battery light came on. 13 minutes later every indicator light on my dash lit up. I was able to get the car off the highway and to a gas station where it died. I eventually was able to get the car to mechanic. It seemed to be the alternator. The alternator and alternator belt were replaced (Friday). They checked the battery and said it was fully charged.

Monday I drove home (70 miles) with no trouble. The next day (Tues), I had to have the seatbelt replaced, dog chewed through it, so I took it to my regular mechanic. He also checked the battery and said it was holding a charge and had 14+ volts. When I picked the car up on Friday I drove about 25 miles before the battery light came on again. I was at the bottom of a mountain in the middle of nowhere but was able to make it back to the top, but the car died at the top. When the tow truck arrived, the car started up immediately for him and he drove it onto his truck. I was very limited in shops that would honor the warranty on the alternator but I went with who I thought was the best of my choices. The car also started immediately for them and they couldn’t find anything wrong. They checked the fuses, relays, battery, alternator, alternator belt fit, and did a low speed test. They eventually said there must be a bad cell in the battery. So I replaced the battery with a 94R DLG 912 crank/735 cold crank. I picked up the car today (Friday) and 45 miles later, the battery light has come back on.

Did anyone check the codes on this vehicle? I believe BMW uses a body computer and this could be faulty. You need a mechanic that knows a lot about BMW so they can troubleshoot this problem. Throwing parts at a vehicle means “I don’t understand your vehicle”.

I agree with missileman. There is something that people are missing and you need a specialist. It sounds like the voltage regulator might be the problem, and if that is external to the alternator (I don’t know about your car) that would not have been replaced. This could also be a simple case of a ground strap being loose somewhere.

One thing you come to notice after working on BMW’s for a while, you replace very few alternators. Someone is missing something here.