auxillary battery ?'s

sahls01gmc · February 7, 2007

I have a 2001 2500 Sierra 4x4 with the auxillary battery. Recently I was having battery issues, so I have since then replaced both of them since I just got the truck last May, and have no idea when they were changed last. After I replaced the batteries, I installed my stereo system. My thought was to hook up the amplifier to the auxillary battery since it doesn't get used as much as the main battery. Everything worked fine for about a week, and then the amp started cutting out. Thinking it was a ground problem, I tore out the back seat and checked all the connections to find out everything was fine. While I could see the amp, i turned on the stereo to see if it worked. The amp lights up when you turn the car on, but the low voltage light turns on. After finding that out, i went to the batteries to check them. My volt-meter reads 12.3-14.4 respectively for the main battery, and 9.2-9.2 on the auxillary battery. How is this possible? Is this battery even hooked up to the alternator?

Thanks for any help you may have

James

sahls01gmc · February 7, 2007

Anyone know what the auxillary battery controls or how it's hooked up?

sahls01gmc · February 8, 2007

Does anybody know what I'm talking about? All i want to know is what the auxillary battery is hooked up to, and how it works. I've tried to search this topic, but I can't find any results.

James

BBSilverado · February 9, 2007

Does anybody know what I'm talking about? All i want to know is what the auxillary battery is hooked up to, and how it works. I've tried to search this topic, but I can't find any results.

James

There are two different dual battery set-ups in these vehichles. The more common setup is just two batteries wired in parallel with no battery isolator, the other system has a battery isolator installed on the auxillary battery. It seems that you have the setup with the isolator, but that doesn't explain why the aux. battery is not getting charged.

builderpaul · February 9, 2007

Does anybody know what I'm talking about? All i want to know is what the auxillary battery is hooked up to, and how it works. I've tried to search this topic, but I can't find any results.

James

2 dual battery options available. Check the RPO codes.

TP2 is 2 hooked together all the time. If you have this code all I can think of is a break in the cable or connection problem.

8BO is probubly what you have. This is an isolated set up. You can drain the aux all the way down without using the main. The aux is supposed to charge when the engine is running. You should have the isolating circut checked since this seems to be the problem.

sahls01gmc · February 9, 2007

Thanks for the replies. I'll check around on the wiring to see if I can spot any problems. I'm assuming I have the isolated battery too, where "should" wires be coming and going from on the aixilalary battery?

Thanks

James