Bad Alternator?

[Fifty150hs]

Check the voltage output when the car is running. If it is at least 13.7 volts, it's not your alternator. If it's not your alternator, it's probably parasitic drain. Something isn't going to sleep. The telematic unit is the most common culprit.

[cn90]

- The Bosch AL0703N I have in my garage right now (bought 2 years ago) is made in Mexico. Many people on bimmerfest E39 (5-series) use it without any issue, it is as good as factory.

- I am surprised the new Bosch is now made in China.

[Overboost]

Originally Posted by Fifty150hs

Check the voltage output when the car is running. If it is at least 13.7 volts, it's not your alternator. If it's not your alternator, it's probably parasitic drain. Something isn't going to sleep. The telematic unit is the most common culprit.

Another caveat is some theories out there is when the alternator fails, it kills that telematic unit. I suffered a alternator failure and soon after the parasitic drain coming from the common failed telematic unit occurred.

I went to the dealer for my 140 amp alternator. It was expensive but I replaced it nearly 10 years ago and have never had a problem since.

[Fifty150hs]

Originally Posted by Overboost

Another caveat is some theories out there is when the alternator fails, it kills that telematic unit. I suffered a alternator failure and soon after the parasitic drain coming from the common failed telematic unit occurred.

I went to the dealer for my 140 amp alternator. It was expensive but I replaced it nearly 10 years ago and have never had a problem since.

That's what happened to me. Twice. It doesn't actually kill the telematic unit, but it does something to it so it doesn't go to sleep. If you pull the fuse for it and that solves your parasitic drain, then you've identified it. In my case, the first time I put the fuse back in and the telematic worked fine and stopped not going to sleep. The second time I said screw it an pulled the telematic as I wasn't using the blue tooth anyway.

[Overboost]

Originally Posted by Fifty150hs

That's what happened to me. Twice. It doesn't actually kill the telematic unit, but it does something to it so it doesn't go to sleep. If you pull the fuse for it and that solves your parasitic drain, then you've identified it. In my case, the first time I put the fuse back in and the telematic worked fine and stopped not going to sleep. The second time I said screw it an pulled the telematic as I wasn't using the blue tooth anyway.

Yeah, ditto. Exactly the same but I just replaced the TCU with a used fleaBay unit. My 2004 was that year the Bluetooth hands free part of that module was not operational, only BMW Assist. I'm not sure BMW Assist even exists anymore.

$40 for the TCU out of a 2006 and fully functioning factory bluetooth. A little dated now but voice command, phonebook, steering wheel control and help features working perfectly.

[80stech]

Originally Posted by Overboost

$40 for the TCU out of a 2006 and fully functioning factory bluetooth. A little dated now but voice command, phonebook, steering wheel control and help features working perfectly.

Is that just a plug and play replacement ?

[Overboost]

Originally Posted by 80stech

Is that just a plug and play replacement ?

Yep, actually about a 5 minute swap. I did go in with BMW Scanner 1.4 and clear out the previous pairings but all in all in 30 minutes, I was all in.

[80stech]

Awesome! Thanks!