Alternator/Battery Issues

[CJKeller]

So I just ran into some issues with my Z3. My first thought was the alternator went bad, however, I got a replacement and I am having the same issue. The battery is 2 weeks old so basically brand new. I’m not receiving any power from my alternator to my battery and I’m not too sure what it is. I’ve tested everything with a multimeter and got the same power from the blue, green/white, and red cables as the battery. The battery light on the dash is lit up. Has anyone had the same issue and is there a way to fix it without taking it to a shop? It seems like the blue cable when attached to the alternator isn’t putting power into the alternator to tell it to charge and is getting caught at the light on the dash.

[zellamay]

Not sure this will help you: I take my car to Autozone, where they tell me whether it's the alternator or battery, or other. It's free. .... I've been sold a bad alternator. Sure, the store gave me another one, but it was a hassle.

[CJKeller]

Thank you! I’m hopefully taking it tomorrow. I’m worried since it’s running off of straight battery that I may not be able to make it.

[Hoyt Clagwell]

'just a thought but removing your headlight bulbs should help a lot.

[CJKeller]

'just a thought but removing your headlight bulbs should help a lot.

Would this take stress off the battery while driving it on battery power?

[Hoyt Clagwell]

Would this take stress off the battery while driving it on battery power?

It would make for less draw on the battery and allow you to drive a significantly longer way on just the battery with no functioning alternator. I have done similar in the past and have driven fairly long distances on a battery alone. I have not done it with the Z3. Doing this is always a bit of a gamble. I'm not sure what would happen to the electronics/computerized components if you were to run the battery down to zero. I have only done this on older vehicles.

[CJKeller]

I noticed someone had the same issue before and fixed it by jumping power from the red cable to the blue on the alternator. Has anyone seen or done that before?

[tjh54]

I'm having the same issue. I have a 2001 Z3 3oi and the 5 speed manual trans. I'm wondering if it's the under the driver's side dash 80 a fuse? I don't know how to open the fuse holder to check it. Does anyone have an idea on how to open it?

[tjh54]

I'm having the same issue. I have a 2001 Z3 3oi and the 5 speed manual trans. I'm wondering if it's the under the driver's side dash 80 a fuse? I don't know how to open the fuse holder to check it. Does anyone have an idea on how to open it?

[s8ilver]

I'm having the same issue. I have a 2001 Z3 3oi and the 5 speed manual trans. I'm wondering if it's the under the driver's side dash 80 a fuse? I don't know how to open the fuse holder to check it. Does anyone have an idea on how to open it?

The cover over the distribution block just pops out with a single clip on the leading edge. The 80A fuse is a bit fiddly to remove (need a socket, and it's tight when you have a clutch pedal), but it's the first one used (2nd position, 1st is blank). However, don't think the car would start, as that fuse supplies voltage to the DME. You would just crank without fire, and have zero voltage at the DME fuses. I learned all about this when I kept blowing fuse #26, which is also apart of that circuit.

20210605_223348.jpg20210605_223708.jpg

There are fusible links close to the battery itself. Follow the smaller hot wire until you find them, then check voltage either side. Not sure where they reside in a Roadster, but look like this in an M52TU Coupe.

20210605_133854.jpg

[tjh54]

The cover over the distribution block just pops out with a single clip on the leading edge. The 80A fuse is a bit fiddly to remove (need a socket, and it's tight when you have a clutch pedal), but it's the first one used (2nd position, 1st is blank). However, don't think the car would start, as that fuse supplies voltage to the DME. You would just crank without fire, and have zero voltage at the DME fuses. I learned all about this when I kept blowing fuse #26, which is also apart of that circuit.

20210605_223348.jpg20210605_223708.jpg

There are fusible links close to the battery itself. Follow the smaller hot wire until you find them, then check voltage either side. Not sure where they reside in a Roadster, but look like this in an M52TU Coupe.

20210605_133854.jpg

Thank you very much!