Battery light on
 

Hi guys,

It's been a while since my last post, but now I'm confused with some electrical gremlins that started happenning in my X5 4.4 in the last trip to the shop.

I sent it over to my mechanic to change guides, chain, gaskets, etc, as preventive maintenance and in hope to reduce the noise made at startup and the diesel clatter when warm.

Well, my guides weren't that bad yet, but still we opted out to change them anyway, I bought them already anyways. The noise still persist at startup and warm, meaning probably Vanos issues (no codes yet), but that's not the part I'm worried about.

The thing is that it came with the battery light on, no flickering, no off anytime, just on all the time. I personally repaired the alternator myself (water cooled) with oem parts Bosch brand about 7 months ago also as preventive maintenance, it was ok before the last visit to the shop, and still is charging battery correctly, measured through OBC option, with digital voltimeter and with oscilloscope, there is no issues I can find, and worst part is that neither INPA, ISTA-D, or a good bmw scanner is able to find anything at all related. There are no codes at all!!!!

Car performs well, voltage is sustained at 13.6-14.4 Volts while running.
I have no clue of what's going on.

Can someone give me a hint of what might be going on? The shop owner told me they couldn't find anything wrong with voltage either, and it's being a month or so since I picked her up.

I'm pulling my hair with this electrical issue.

Please help!!! :dunno:

One would think the cluster is acting up. For what it's worth, I would disconnect the battery cables for 10 minutes and then touch the disconnected cables together for 10 seconds to clear any memory issues, then reconnect the cables to the battery positive first and then negative and see if it solves the problem. I am not sure it will help but when nothing makes sense, it's the first thing I try. Doesn't cost you anything except 20 minutes of you time.

At this point, I'll do almost anything to clear that freaking light. It drives me nuts.

I'll try that out again. I already did it, even changed the battery to a new one and still nothing.

Just make sure to touch the disconnected cables together to clear any frozen memory issues.

As an update, I still have the battery light on all the time.

However charging system seems ok since battery is always good to start the car and there is no fluctuation whatsoever. I can't find any issues besides this freaking light on.

Tried the method Overboost mentioned with no luck for more than 10 minutes.

I'm just starting to learn to live with it. The only sporadic error INPA gets from IKE sometimes is error 90, Clamp 15, open circuit.

Any suggestion would be very appreciated.

Have you checked the voltage when the car is running? You should be getting 14v+. If not, you have a problem. Probably a slow alternator failure.

Is it possible the key on voltage (KL 15) to the cluster is faulty?

Maybe check fuses, the shop might have shorted something out when they where working on it.

The thing is that I personally rebuilt the alternator with bosch parts, it wasn't failing before but I had all the parts already and I was doing a bunch of work of the cooling system, so it was already out.

It worked flawlesly about 4 months until I went to the shop, they told me they didnt' remove the alternator and they checked all the plugs. I'm not so sure about this because from day 1 I lost my PS function, and it was bc they forgot to plug the PS.

Voltage has been checked by digital multimeter, scanners, oscilloscope, and OBC, never goes beyond 14.2V or below 12.9V (only during stops but this is due transmission), then 13.6V is constant.

This is my last spot to check, however I've no clue how to test it. Do you know how?

I already checked the relay in e-box, cleaned the metal contacts well just in case.