:iagree:

Charged battery last night to 12.8v (disconnected from car) and 12 hours later battery now reads 12.98v so no lost charge overnight.
I'll take it to a local battery place later but I did do the test whereby you test the voltage with the engine cranking (underload) it dropped down to 10.5v then shot back up so I assume this is ok, do I still need to get it checked out or can we now say it's ok and move on to the ABS lights?
I rang a 2 auto electricians yesterday, they sounded interested in looking at it until I told them what tests is done already, they said they wouldn't be able to any more than that! So I'm on my own..

If I know the alt and battery are working fine I'm not overly concerned about the battery light being on, obviously I would love to fix it but if it's not causing other issues I'm happy to move on, if however the light being on is causing the ABS issue they yes it needs to be sorted. I just don't know what to check next, I'll go to my local battery store this morning to have one final check of the battery. What do you suggest after that? The auto electrician I spoke to on the phone yesterday said the battery light on this model comes from the ECM hence why he didn't want to know after that! I had a look on YouTube on how to remove the alt to that I could see the wiring, I can get to the front connector which looks to have two spade ends that I could check the voltage on? After that I guess I'd have to check the ohms/voltage going to the battery light bulb?

Do you know if it's possible to remove the cluster and check the voltage to the bulb? It's a public holiday here so I can't take it for a battery test just yet. I'll also double check all of the connections around battery, alt, grounds etc today.
One thing I didn't mention, whilst driving a few of the other lights (fuel gauge, MIL and something else) flicker every now and then, all at the same time-not sure if this has anything to do with it, when my mate had the code reader attached he kept getting steering angles sensor faults plus "brief power interruption"...

Ok, I have a blue and green wire coming from the alt, I pierced the blue with and got 15.3v,it seemed to fluctuate a bit but that could have been me moving the wire..

Stevo; It appears the battery is OK, and from he voltage shown when running, the alternator is working. But as already stated, these are fussy cars, with very sophisticated electronics, and yours is telling you it's not up to snuff. It's time to throw in the towel, and either bring it to a dealer or a good specialty shop that has some better diagnostic equipment. If you're looking for an independent shop, the very first question should be: 'Do you have an Autologic with up to date BMW Software". If the answer is no, move on. Once they sort the battery light, ask them to see if the Autologic can communicate with the ABS module. If the answer is no, tell them to NOT fix it. If it's a bad sensor, that's up to you, but likely not crazy expensive.

Either the ABS problems will solve themselves when all voltage issues are fixed, or they won't. If they don't, often the module is completely out to lunch. While it could be a sensor, if its the module, you can either: Put in a new part, then have it coded, ($1,500 part.). Put in a used part, and have it coded, ($750 part). Or send your module out to one of the rebuilders on eBay. If you're lucky, $100, and then recode. If you're not lucky, another $400 and they'll send you a rebuilt unit. No matter what, the unit will need to be coded. But to attempt this with a battery light on is silly; these cars are known to throw the trifecta lights when voltage is not perfect. Sort that first.

The ABS module in the X5 is in a very bad spot. It's about a minute to remove from a 5 series, but on the X5, you need to remove the left side headlight, and the whole assembly with the oil filter, power steering reservoir needs to be moved aside. Given the location down below the headlight, mine was completely filled with muck...no wonder it failed.