Ok so my battery light is on (97 528i) checked the alternator, its good. Took the battery out and put it on a load tester. also came out good? whats the deal? anyone else have this issue?

~Nick

How did you determine that the alternator was good?

How did you determine that the alternator was good?

+1

hooked it up to a load tester. it passed with flying colors...

...anyone have any other ideas?

There should be a sensor wire hooked up to the pos + post. Usually that will pop off. Rare but worth looking at. A dead battery might also come to fruition a little later on regardless of load test. Keep some cables handy.

dont forget to clean your terminals... do it while its off... save yourself a ton of grief

Sounds like the regulator on your alternator has failed. It tells the car that battery is being charged, once this fails the car thinks the battery has a low charge. You could leave it like that but keep in mind that when your alternator does fail you will have no warning.

I do not know if you simply fix the regulator, more than likely you will need to replace the entire alternator.

i did try a new battery in the car and was having the same issue. However something that i realized is if i let the car idle, the light will stay on, as soon as i rev the motor it goes off until the rpm's drop then it will turn back on?

I was kind of leaning to thinking the regulator was bad, but really have not way to check on a internally regulated alt. Unless someone knows a way?

Thanks for the info guys, i'll check on the one pos + wire.

thanks again

~nick

just to let everyone know, i tested out the regulator and it was bad...

...and a tip for someone

Alternator at BMW $600 with core charge

Price of mechanic to change it $400

price of buying it at AutoZone and installing it yourself $200

satisfaction of knowing you saved yourself $800 priceless

:D

:buttrock

When purchasing a new used/rebuilt alternator, say from pelican parts or a Bosch one from Kragen does it come with a new voltage regulator?
Reason I'm asking is that today after work when I started up my car, the battery light came on then went off after a while. Also the light came on and off randomly on my drive home.

On another note, would it be ok to use the 140amp on my '98 528i or just stick with a 120amp?

When purchasing a new used/rebuilt alternator, say from pelican parts or a Bosch one from Kragen does it come with a new voltage regulator?
Reason I'm asking is that today after work when I started up my car, the battery light came on then went off after a while. Also the light came on and off randomly on my drive home.

On another note, would it be ok to use the 140amp on my '98 528i or just stick with a 120amp?

Yes, one from Kragen does come with the regulator. In fact I just bought the Autolite reman and it has a lifetime warranty and 24mo roadside assistance for 165 bucks. You might want to order a couple of pulleys (idler,tension) also and replace them while your in there.

Did you get an AutoLite 120amp?

Anyone have any opinions on the AutoLite alternator?

Also, if you've replaced your Alternator what brand did you go with?

Did you get an AutoLite 120amp?

Anyone have any opinions on the AutoLite alternator?

Also, if you've replaced your Alternator what brand did you go with?

I did get the Autolite 120amp, When I worked for Kragen about 10-12yrs ago I seem to recall that there may have been some problems with alot of warranty returns on Autolite rebuilds. If you did not know when they rebuild alternators they usually only replace the regulator, bearings, and brushes not the windings. I supposed since the warranty is so good and they have roadside assistance than you can't really go wrong except for the labor. I believe they have an internal claim process that may cover labor also if you pitch a fit.

just to let everyone know, i tested out the regulator and it was bad...

...and a tip for someone

Alternator at BMW $600 with core charge

Price of mechanic to change it $400

price of buying it at AutoZone and installing it yourself $200

satisfaction of knowing you saved yourself $800 priceless

:D

I have a 97 e39 540i and thinking of replacing the alternator. Do you guys advice going oem or will an autozone one be ok? if so, which one?