alternator problems

[X53Jay4.8is]

Originally Posted by FREE-PPV

Greetings,

New here, so I have a question perhaps someone can answer. I have 03 X5 and battery light came on, replaced battery a couple months ago, and now alternator died as there is no voltage coming out of it. This is water cooled monster. Changed one on my 545i a couple years ago, so I broke the old one open and the regulator readings across two terminals was open one way, and not the reverse continuity.

So my question is, I have found that most people say the regulator goes bad, so has anyone done any diagnostics on regulators, as in put meter on connectors to see what the reading is in ohms. I was thinking of rebuilding the old one I have had or just change regulator, but was wanting to know if anyone remembers continuity test.

Thanks

Do yourself a favor and avoid a returning headache by just purchasing a new alternator to replace your defective one. So suppose you do the regulator fix, 3 months later bearing whine comes into the picture. Then you will be back at replacing the alternator. By the way why did you not check the charging system when the battery light came on? It would have produced the results of a failing alternator.

[FREE-PPV]

Originally Posted by X53Jay4.8is

Do yourself a favor and avoid a returning headache by just purchasing a new alternator to replace your defective one. So suppose you do the regulator fix, 3 months later bearing whine comes into the picture. Then you will be back at replacing the alternator. By the way why did you not check the charging system when the battery light came on? It would have produced the results of a failing alternator.

Thanks, and you may be correct, but I am old retired electronics technician, from the old school, from the repair over replace era. lol It was obvious when the battery light came on that it was alternator as I had replaced battery a few months earlier, doesn't take a rocket scientist to know the vehicle would not run for long on battery power alone. Was able to get home, barely, and battery was dead, wouldn't restart when I put on voltage meter. Charged battery, checked again, only 12.1 VDC while running. Checked connections at alternator, belt, etc., so pretty obvious.

So here was my reasoning, replacing costs up to $600. and a regulator is $60. and diodes are $6. each. So I pulled it apart and bearings are smooth and noise free, no sign of wear at all. Regulator has open circuit when doing continuity test, while new one does not, so I know there is a problem with regulator. Started to check diodes, one had corroded leg which was broken and one was shorted, probably what caused regulator to go bad, so with that, figured I was safe in just ordering the diodes and replace the regulator and in the end, I save several hundred dollars. Mechanics will just try to sell you a new alternator and with labor, hit you for a grand, some of us don't have the money to waste, bottom line, so will update results when I get diodes which I will replace all six given when one goes, they all will eventually.

Thanks,