So yesterday the red battery light came on my dash. I read into it and found out its the alternator not supplying the battery with the juice she needs. Anyone had this problem before? Do I just need a new alternator?
It could be one of two things... either your alternator is tango uniform or your battery is toast. First; How old is your battery, and is there a shop that can load test your electric system? Secondly are you getting any other unusual dashboard lights?
V/R Zachary Pullins Sr.
Florida Suncoast Chapter BMWCCA
2016 Cadillac SRX & 1999 E39 540i/Sport
" Vision without resources is just hallucination"
Update, I had my diagnostic reader in as I was attempting to drive it home, started lagging so I checked the data and it said fuel system 1 off and fuel system 2 off., friggen died on my on the busiest street in rush hour (it was the only way to get to my place) it was so dead that my 4 ways wouldn't even come on. I'm thinking it might be the battery because doesn't it usually charge itself up while your driving? And if it died while driving (twice) then the battery isn't holding. I charged it to my buddy's car for 10 mins and I was able to make it home. Now the fun starts. I'm gonna take the battery in tomorrow to get tested
Update, I had my diagnostic reader in as I was attempting to drive it home, started lagging so I checked the data and it said fuel system 1 off and fuel system 2 off., friggen died on my on the busiest street in rush hour (it was the only way to get to my place) it was so dead that my 4 ways wouldn't even come on. I'm thinking it might be the battery because doesn't it usually charge itself up while your driving? And if it died while driving (twice) then the battery isn't holding. I charged it to my buddy's car for 10 mins and I was able to make it home. Now the fun starts. I'm gonna take the battery in tomorrow to get tested
Update, I just got home so I was able to search the web and it turns out it's the alternator isn't charging the battery. Then the car runs on the battery till it dies. Time to make my wallet anerexic seeing as I don't have the shop anymore
Last edited by 1235kjd; 10-24-2011 at 07:32 PM. Reason: Automerged Doublepost
Often, an instantaneous red battery light is indicative of a broken accessory belt. If the belt comes off or breaks, you'll no longer have power steering, alternator, or (most important) water pump. Continuing to drive in this condition will present a severe risk of overheating and engine damage.
Your first step would be to check to see if belts are still intact.
If belts are not intact:
- Check idler pulley and tensioner pulley
- Check water pump bearings
- Replace/R&R as needed
If belts are intact:
- Check battery terminal connections
- Check connections at back of alternator
- Check ground cables
- Check voltage at battery terminals while car is OFF - should be approximately 12 volts
- Check voltage at battery terminals while car is idling - should be approximately 14 volts
- Check voltage at battery terminals while car is revved up a little (maybe 3k-4k RPMs) - should still be approximately 14 volts.
If voltage is irregular while the car is running, it might be the voltage regulator which is part of the alternator. But, replacing the voltage regulator is just as much work and almost as expensive as a fully remanufactured alternator... so if you're certain the connections are all good, and you're not getting a consistent 14 volts at the battery terminals while the car is running, then I'd probably go for a remanufactured alternator.
All connections are good, belts are good, etc.
The car is completely dead so I can't check the battery and what not.
What all should I replace while I'm down there doing the alternator?
There's not much else that you need to remove to get to the alternator.
If you're really looking for a "while you're in there," then maybe look hard for any evidence of a leaking oil filter housing gasket. Shine a bright light down in the hole behind the oil filter housing, look for grime and oil on the waffle-textured area on the side of the block. If it's dirty there, you likely need a new oil filter housing gasket. The part is cheap, and it'll take maybe an extra hour to replace that while you're doing the alternator. The alternator has to come out to get to the gasket, so if it needs to be done, now's a good time.
Otherwise, just do the alternator and be done with it.
You can probably pull the alternator and have it bench-tested at an auto parts store... just to be sure.
Asesome, thanks! If I need a new alternator, what size amp should I be using?
I don't remember, other than that there are at least two versions. I think there's probably a sticker on your existing alternator that should tell you what you need.
Wow. Dtealer wants $950 plus $100 core. Yet online you can get one for 200... How do they sleep at night? Wait I know.... In a bed of stupid ppls money!
I believe that if you go to a BMWNA dealership, and have a new alternator installed by them, it'll carry a lifetime warranty*. So, there's that.
Still, one or two more $200 alternators should last the life of the car.
* last time I went to Fields BMW in Orlando, they had a sign in their service department stating this. That was a few years ago though.
K so I took my battery in to get charged. It was put in back in feb 08. Turns out the battery is no good... I'm gonna pull my alternator out to get checked in a few days also
How come?
3 years seems to be an unbelievably short life span for a battery.
iirc, the BMW battery is guaranteed to last 10 years, no?
Is there any warrenty on a BMW battery?
I would think it would follow the warranty of the car. Dunno.
I just don't want to buy a new battery and put it in my car and it turns out my alternator is pooped too and kills the new battery lol
K.. So I they charged the battery and told me that it was bad... I decided to test the battery with my tester and it was putting out 14.... Isn't 14 good?
Was car running?
Nope, it's not hooked up
Last time I heard BMW battery's had a 1 year warranty. Your alternator should have a label on it and it will say for instance 120a, 140a ect meaning the amperage out put of the alternator and it would probably say Bosch or Valeo also you do not want to install marginal battery with a new alternator, it could damage the new alternator
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