Greetings all I have a feeling this is going to be a bit of a nightmare, but here's hoping someone knows what it could be. I have started having a "battery charging fault" today. The last activity of note carried out on the car was last week, a subwoofer fitting in the hoot. Wired normally, nothing special, tiny subwoofer. The fault seems to happen when driving harder, but in a strange way seems to go away when braking. Beyond this I have disconnected the battery and reconnected it, everything is secured. I have noticed others have said it can be earthing straps - but I don't know where these are. If anyone can let me know specific locations I could get under the car and check? Otherwise has anyone else solved this without the nonsense of changing alternators and regulators, etc. As I don't think these are the issue. Cheers
There are a number of earth points. Some of which come from the negative side of the battery, and there's another on the gearbox which goes to the chassis rail. It could just be a coincidence, but generally that fault would indicate an issue with your alternator.
Thanks. It can't hurt to try and find and check the earthing points I suppose. Do you know specifically where they track to? Are you saying that both cables attached to the negative terminal go off to an earthing point? If so I'll follow them and check if possible. Besides all this, I've seen people even suggest it can be caused by low brake fluid level (?! - maybe the wrong error?) earthing/grounding connections, regulator, battery (mines dated 2023 so pretty new) and then the alternator. The fault is totally intermittent at the moment and seems to be linked to the type of driving. Yesterday it seemed intrinsically tied to when I pressed the brake pedal, it would often cause the fault to go away immediately. Which was odd and possibly a coincidence - I have no idea.
If you do work on a car and there's something wrong afterwards it's likely to be something to do with that work. I'd be retracing my steps regarding the subwoofer install before getting into the weeds with earthing points.
It sounds like it may be a loose connection - more than a shitty alternator; but you never know?? Where and how was the sub-woofer connected??
The subwoofer power was connected to the battery terminal as in the photo. Other than this, nothing else was changed. The battery and airbox were removed to access the firewall I believe, but the guy that fitted it actually said that the airbox had been put back loose by whoever did it last so he'd tightened everything up, he seemed to know his stuff and be diligent.
Try disconnecting the subwoofer, and does the issue go away? If so it probably has something to do with the connection point. As you can see in the attached, the protection and switching unit splits the electrical loads into 2 parts - starter circuit+ essential controls (5A fused supply) and auxiliary circuits. From what I can tell you've connected on the starter circuit+ essential controls, and either based on the load or sub woofer internal p/supply disturbance (ripple?) may be affecting the essential controls/monitoring charge etc. If disconnecting it solves the problem, try relocating to the otherside of the load switching relay. Also check the plug connector onto protection and switching unit is secure etc Long shot but may solve it. Good luck
Thanks I'll have a go at this. Where is the other side of load switching relay please? I.e if this does solve it where is the best place to reconnect to in order to solve the issue? I must admit it crossed my mind that maybe the connection location had influenced this but also thought surely it wouldn't make a difference. But the intermittent nature of the problem (sometimes the warning goes away in quite literally 2 seconds) suggests it's something like this, rather than a bad alternator.
Box immediately to the right of the circle on your photo I would fit a fuse splitter in the fuse box in passenger foot well - as what I did for supply to my wide band O2. See photo. Depending on current draw by your sub woofer (let me know) and I can look at best spot/circuit
Hi, I've just disconnected the subwoofer this morning and done a run around the shops, max 7 miles of driving. The fault came up once for around 15 seconds, which is still in line with frequency it's been happening with previously. I've left the subwoofer disconnected anyway until I get this sorted. I noticed when switching my headlights on and off that the RS monitor and my aftermarket head unit displays dimmed simultaneously due to the increased draw. I haven't noticed this before. I have an OBD but I suspect it won't tell me much at this point. I better hook a multimeter up to it when I get a chance but I won't be able to for the next couple of weeks due to work commitments so will have to keep fault finding then. I appreciate your replies and help with this though, is there anything else you think it might be that I can check?
Seems to indicate maybe you do have an intermitent charging (alternator) problem. Worth doing voltage check to see if it is charging, but as its an intermitent I guess it will come up ok. These posts & videos may help https://www.renaultforums.co.uk/thr...xed.514713/page-3?nested_view=1&sortby=oldest If the brushes are occassionally hanging up/not making good contact, your comment "The fault seems to happen when driving harder, but in a strange way seems to go away when braking." may make sense. I had volvo years ago which had a similar problem to yours, but the fault light was continuous - to get me going the RACWA breakdown guy used a metal shaft and hammer to give a short sharp knock to the brush holder, and Bob's your uncle - all fixed. Good luck
Thanks for this. Yes all of these problems could be the culprit. However messaged the previous owner to ask what the small red wire running through the bonnet was, and he replied that he had to have diagnostics and tests run to establish... drum roll... the source of an intermittent battery charging fault! And that this wire was the solution but couldn't be pulled through the main loom so it was added from the ECU area to the alternator. I believe it is the alternator signal wire and can give off a charging fault if the connection is iffy. So now I'll have to get that looked at to see if it's come loose due to the subwoofer man pulling out the battery, airbox, and ECU(? - I think this too). Maybe this will show up as the issue. I'll report back in due course!
Just checked the receipts for work done in the car purchase pack and there was work done in mid 2022 outlining what I've mentioned above. Alternator was replaced in trying to find a solution. Further diagnostics determined there was a 921114 UPC short circuit to earth fault - which could explain intermittent nature as I'm getting a spanner light as well. The remaining detail covers signal wire from alternator was tested and showed weak signal so, corroded/damaged. This was replaced and fixed everything. So it seems that subwoofer man has likely knocked something loose or dislodged something slightly, and I'll have to plug in an OBD to look for that fault and get the alternator signal wire tested again. Will update when I find out what is going on.
Glad you sorted it out That signal wire actually tells the alternator to begin producing current - ALTERNATOR SYNCHRONOUS BIT SIGNAL (CHARGE SIGNAL MANAGED BY UPC)
