Started getting this a few weeks ago. Say visit workshop and has a picture of a battery in red. Car would sit overnight and I would get this message in red. One time I let car sit for two days and the battery was dead. Went out and had system tested. Alt was putting out good voltage and they even said my battery should be good. Well I replaced the battery anyway.

Did get error for a few days this time. Then it came back. Battery has never died but now I get this message all the time. The last week it was just doing after sitting overnight but now it will do it after sitting a couple hours. Car always starts at least.

suggestions ?

 

Auxillary battery under the hood, the small one.

 

Yep! Just replaced mine last month and all is good now.

 

Where under the hood exactly?

 

passenger side of the car under the black plastic cover near the firewall

 

$66 on Amazon with free shipping (Prime customer)

ACDelco ATX14BS (14-BS) Maintenance Free Absorbed Glass Mat (AGM) Powersport Battery


took me about 10 minutes to install

 

Thanks, I'll try that next.

 

I just read on another thread where they state the aux battery is only used if the main battery voltage is low ...


"

 

Your voltage regulator on the alternator could be acting up. When the prongs get worn on them they will alternate from correct voltage to less until it just won't charge at the correct voltage anymore. So when you had the system tested it could very well have been working fine at that time and then started acting up again later.

May not be the problem, but just something to keep in mind. They are like $75 and about 15-20 minutes to put in from under the car.

 

This information is incorrect. The auxiliary battery is a dedicated battery for SBC. In the event that you would have a complete electrical systems failure, you would still be able to stop your vehicle safely.

 

Hey guys I've been searching all threads about red battery warning lights here for weeks and see a lot of different cases with different causes leading to the same issue. And since the charging system comes with so many controllers, that's what got me lost. Sometimes it seems to me that I knew what the problem was since I had done some diagnostics on the system, but when I intend to replace what I think is the cause of the problem, I hesitate and get confused for fear of replacing the wrong part . Pardon the length of the introduction. In general, before discovering this issue, I had done something on the same day that may have been a mistake and the cause of the problem, and it may not be, but before I say what I did to it, I will tell you about the state of the charging system before, in order to avoid the possibilities of wrong diagnosis. Exactly a year ago I had a battery drain issue, so I assumed the batteries were bad, since they were around 5 years old,so I put new batteries from mercedes dealer but it didn't solve the issue, next I replaced the voltage regulator but did not solve it aither. after that I had to go harder with the diagnosis, at the end it was the front passenger seat control module, replaced it, and everything becomes fine, After that I didn't drive it for six months as I went to another state for work and now I'm back. Of course the battery was disconnected, and here I will mention the thing I did that made me suspect that it could be the cause of the problem, and without it I would have suspected on the alternator only. since I don't know how old it is. Ok what happened is my trunk can only open when the system is powered, so It can not be open with the key blade due to bad trunk lock, so I had to connect my battery charger at 2 amps settings to the alternator. the red clamp to the B+ terminal connector at the back of the alternator and the black clamp to a ground point. I got the trunk opened and recharged the batteries and Guess what?!! I forgot to reconnect the auxiliary battery terminals and started the car. A few minute later, All Electrical consumers started to turn off one after another. I remembered that I forgot to reconnect the auxiliary battery so I reconnect it back and started the vehicle again، But nothing changed for the better, and after about ten minutes the red battery sign appears. That's when I realized that the car running off the battery not the alternator, so I checked the voltage on the alternator with the car on and off and it was the same voltage as of the battery, so the alternator doesn't produce any power, because the voltage doesn't increase when I start the car. now the question is, Is there a possibility that what i did caused the system to short out? I'm suspecting a shortage either on the auxiliary battery relay or the ×4/10 fuse. i know I've said a lot but hey it is a nightmare I am sure that everyone who has suffered from this problem feels me, and I hope everyone who has experience and can help does not skimp on me. any help will be appreciated, thanks