Diagnosing an alternator - Battery not charging

Brunoandrade98

Paid Member
Hi all,

I need help diagnosing a possible alternator issue.

Yesterday, my car started misfiring, the engine light came on, and I got "Braking fault" and "Low battery" warnings on the dash. The engine then wouldn’t start—just clicking sounds that would turn the dash off and on repeatedly with some dash lights flashing, needles doing slight sudden moves. Also, at this point, the hazards were stuck on.

I charged the battery overnight, and the car started fine this morning, but the "Low Battery" warning reappeared after idling.
The battery measured 12.6V with the engine running and 12.9V when off, pointing to a bad alternator.

Battery was hooked up to a tester and tested "Okay". Not new, but not bad, and the parts shop dude advised me against replacing the battery (yet).

Before I replace the alternator, is there anything else I should check? All fuses around the battery and in the UPC are fine after checking with a multi-meter, but I haven't checked the relays since I'm not sure how.

I find it very strange that the alternator would die after the car being sat. But you never know...

I attached various photos of the fuses plus some screenshots of some faults in CLIP.

Any help will be much appreciated.

Thanks in advance.


Some information I'll add, but probably not relevant:
I had to repair some of the wiring that connects the dashboard harness to the rear harness (rear lights, speakers, etc), and had that's why the car sat for a few weeks without turning the engine on. The battery was good before I started working on the wiring. The wiring was repaired by myself to a very high standard and I'm very happy with the results, and everything worked as it should. The reason why the wiring had to be repaired was due to water damage from the sunroof drains on the bulkhead side. I checked, and this was the only damage caused by the water, as the water skipped everything and just pooled in the floor pan.
 

Attachments

  • IMG_4965.JPEG
    IMG_4965.JPEG
    965.4 KB · Views: 6
  • IMG_4966.JPEG
    IMG_4966.JPEG
    843.7 KB · Views: 7
  • IMG_4968.JPEG
    IMG_4968.JPEG
    985.1 KB · Views: 8
  • Capture2.PNG
    Capture2.PNG
    78.5 KB · Views: 8
  • Capture0.PNG
    Capture0.PNG
    76.8 KB · Views: 8
  • Capture1.PNG
    Capture1.PNG
    69.5 KB · Views: 5
  • Capture.PNG
    Capture.PNG
    82.7 KB · Views: 6
  • Screenshot 2024-08-09 133731.png
    Screenshot 2024-08-09 133731.png
    1.2 MB · Views: 6
  • IMG_4667.JPEG
    IMG_4667.JPEG
    826.8 KB · Views: 6
Your intitial description sounds like battery or earth but the low battery error is pretty standard and is always the alternator (regulator) assuming your earths are all good.