Alternator / battery light!!!!!!

If you have a Bosch alternator in there and decide to change it out...MAKE SURE YOU GET ONE WITH THE RIGHT VOLTAGE REGULATOR. There are 2 different connectors: an oval one and a rectangular one. There is no real rhyme or reason for which cars got what (the oval connector was originally for the Z4, but many E46s got them, too). So take your old alternator out before ordering the new one.

Ok, so will the "compact" alternator work on any e46 or did only certain models come with this?

As I said before, the new remanned Bosch that I got from WorldPac is interchangeable. I know it was interchangeable with my valeo, but not sure about this oval/square connector issue...which I recall hearing about before (see Cak323i...I think he wrote about this).

But, it might be interchangeable with that too. My plug was rectangular...and the bosch fit, even though I had a valeo.

Sometimes I wonder if bmw does stuff like this randomly, so whenever you take your car to non-dealer for repair, it always takes longer, and you always here some excuse like, "we had to get a different part, because the one you should have isn't there"?

So it has new battery, the voltage at the terminals seems ok, but battery warning still lit occasionally?
Did you check the voltage readings on the fuse ends inside the glove box?

OP...in re-reading, I'm unclear about whether your voltage of 12.5 was when the car was off or on? If on...it definitely could be the alt...but you will have issues if any cable is loose or corroded. Doublecheck your work on the alt...I hope you get lucky and 'tighten/clean' your way out of your problem.

Remember if reusing belts, to keep them the same direction. Mark them, or note the direction the lettering is facing.

12.5 volts is when car was running. How on Earth do i check it from the fuse in the glove box?

Originally Posted by Wormydog

12.5 volts is when car was running. How on Earth do i check it from the fuse in the glove box?

You don't need to now, I don't think, but you put the probe into the little hole on either side of the fuse. I'm weak on multimeters, but I think you find a ground for the black and touch the red to the hole in fuse. They should read around 12V anyway, even if the alt is putting out 14V.

Anyway, you have an issue with your 12.5 volts. It probably is the alternator...since your car is running, I think if the connection was that bad that you've lost 1.5 volts through corrosion or looseness of connectors, that you'd have a number of other issues.

Just confirm connections on alt, under +terminal, grounds--main engine grounds and the ground by the battery in trunk...where the black cable attaches to the body.

99% it's the alt.

Originally Posted by Wormydog

12.5 volts is when car was running. How on Earth do i check it from the fuse in the glove box?

1. open the glove box
2. turn off the 2 plastic locks on both sides
3. that's the fuse box: http://forum.e46fanatics.com/showthr...t=fuse+diagram
4. measure EVERY fuses connect point against the ground, the measurement should be either 0V or 12V.
5. If the battery warning light on, there must be some point below 12V (that's what the warning light tells you!) If there is any point between 0 - 12V ==> Ignition Switch (You'll be proud of yourself finding the problem, btw, I fixed the same problem before. good luck!:-)

ok thanks, how exactly did you fix it? What was the issue?

Open the plastic covers around the steering column, replace it with a new switch (~$80), stealership would charge you minimal ~$800:-)
The issue is the connection resistance, let's assume it has 1 ohm now, with 5 amperes current, it would drop 1x5=5 V, only 12-5=7V left. :-(

Originally Posted by Heilbronner

Open the plastic covers around the steering column, replace it with a new switch (~$80), stealership would charge you minimal ~$800:-)
The issue is the connection resistance, let's assume it has 1 ohm now, with 5 amperes current, it would drop 1x5=5 V, only 12-5=7V left. :-(

Did you have codes read that indicated ignition switch, or is that another failure that wouldn't register.

I know ignition switch often fails intermittently at first, so that's a very good guess.

Only thing I'd add, OP, is to read ignition switch threads. I know that commonly they'll be some issue at the steering wheel (like turn signals) and elsewhere, seemingly often the radio.

Where you having other 'squirrely' issues besides not starting, before the not starting began?

Well sometimes when I turned over the key if would make a noise but the engine would not even be turning over. I'd have to turn the key back, then try starting again. Sometimes it would do it like 3 times before it would finally turn over the engine

It almost sounds like the starter is spinning but not "engaging"

You need to know if it's cranking or not.

A starter not engaged will, I believe, make a raspy sound...if it's really cranking, you'll hear the entire engine turn...it's a much different sound.

Try doing the cluster test for #9 (voltage) when you try to crank. If the voltage drops down, it's cranking. If the voltage doesn't drop much, it's not cranking.

All the dealer did was charge you $180 and give you a new fuse? Might be time to go back to the dealer and talk to a manager/SA and say, "I just spent $180 for you to diagnose my issue for me, and I still have the issue. Could you maybe have someone else look at it without charging me again?"

When i turn the key, it sometimes just makes a sound as if the starter was just spinning but not engaging the crank.
I don't know what the 180 dollars ur talking about

Originally Posted by Wormydog

When i turn the key, it sometimes just makes a sound as if the starter was just spinning but not engaging the crank.
I don't know what the 180 dollars ur talking about

Sorry...too many threads to keep track of...lots of no starts...sorry.

Check the voltage drop when cranking...it would grrr grrrr and not 'whizzz whizzz' if it's cranking.

Maybe post a vid?

Originally Posted by Heilbronner

The issue is the connection resistance, let's assume it has 1 ohm now, with 5 amperes current, it would drop 1x5=5 V, only 12-5=7V left. :-(

No, just no.

It could be ign switch, but starter is far more likely. The only way to know for sure is to check the voltage supply to the starter itself. However, a bzz noise and no cranking is pretty damning if you have a good battery.

its not cranking when it makes the noise, it makes a whirr sound. Id love to post a vid of the noise it makes, but it makes it at random times... haven't had any problems since replacing the battery except for the battery light does still come on.
But the terminal under the hood of my car is crazy frickin hot, battery terminals on battery in the trunk are not hot. I read somewhere that that could indicate something was wrong

I would check the connections and especially the grounding wires/strap.
A frayed or loose grounding strap for the alternator or block would cause this intermittent charging issue. If the alternator (or internal regulator) isn't doing its job to sufficiently power the car and charge the battery the light should go on.
This would also make the battery's charge low and not enough to start the car. But since it starts the car with a jump I see no signs it's the starter. *Although a poor connection to the starter would not allow full CCA from battery so if anything starter related it could be those wires. (but likely not)

Are the grounding straps ,for the block ,your talking about the ones bolted to the ignition coils?
The light comes on as if it were telling me a message in morse code, comes on and stays for a couple seconds then goes off then comes on for a half second then back off and so on...never really stays on permanently.
Should the terminal under the hood be crazy hot?