Brake Abs vsc lights on.

Possibly. Charge the 12 V aux battery up with a smart 3-4 Amp charger suitable for AGM batteries and if it can achieve 12.8-13.1 V and hold that overnight, that may be all it needs. If it drops quickly (within 48 hours) to < 12 V, you should start shopping for a new 12 V battery.

 

Also, please do collect the codes from your brake computer as to why it is lighting your brake warning lights and sounding your brake warning buzzer. I understand why people would hope that low voltage on the 12 volt battery is the total explanation of everything, I only have one question to pose:

Do you think it is more likely that your brake computer turns on your brake warning lights, and sounds your brake warning buzzer, to tell you that your 12 volt battery voltage is low, or to tell you there is something you need to know about your brakes? Possible? Sure, yeah, maybe possible, but more likely than that the lights and buzzer mean what they were put there to mean? As in, feeling so confident making that bet as to not even bother to read the codes and find out what the computer might be telling you about your brakes?

If so, you feel luckier than I do....

-Chap

 

All things being equal, then yes, I would agree.

But, I don't think the brake computer turns on the brake warning lights, and sounds the brake warning buzzer, to indicate the 12 volt battery voltage is low, rather that a low voltage on the 12 V bus causes a disturbance in the force such that the brake computer does not know what it thinks and so lights the light and rings the buzzer.

While it is still possible that there is a genuine brake fault, the first course of business is to rectify the 12 V so that it supplies good clean voltage within the spec'ed envelope. Once that is done, clear the codes and then see what codes come back. If there is indeed a genuine brake fault, the appropriate codes will reappear.

If codes reappear, was it a waste of time looking at the 12 V and charging/replacing it? No, it needed attention.

I understand that it can be frustrating that a lot of the time the first question is, "what is the state of your 12 V?", but if it wasn't a factor so many times, it wouldn't come up. It is almost humorous that such a small component can cause so much aggravation.

 

Have you done anything else, my lights just came on!