2011 Yukon XL SLT baterry dies

[AmazinglySmooth]

Dealer replaced the battery in my 2011 Denali. I'm hopeful it will fix the underlying issue, but only time will tell. Something is bad about these batteries or the fancy charging system employed.

 

[HOE-N-IT]

09-08-50-17b. it has been revised once at least to add other vehicles perhaps it has been updated again. ant any rate it firmly recommends that even if the dealer cannot duplicate the problem they, regardless, should check for revised calibration on TIS2WEB.

hope this can help.

Thanks, I looked it up and it was for 2007 through 2010 models built before 11/30/2009 so I should be good but it may be part of 02lightning's issue since he has a 2008. BTW you left a 0 out of the TSB number. It should be 09-08-50-017b for anyone else that wants to look it up.

 

[02Lightning]

Well, I didn't try to start the car or see if my dash lights worked with just the 2nd battery but I can't see why they wouldn't. The positives are connected together at the starter and both negatives are connected to the motor so the 2nd battery will be connected to the vehicles electrical system. I can't imagine a diode is wired in the cable to the starter from the main battery.

If your sure you connected it to the same lug on the starter as the main battery and it won't power the vehicle electrics I'll go disconnect the negative from my main battery and check.

BTW while not related to the above did you get 2 new batteries?

---------- Post added at 06:56 PM ---------- Previous post was at 06:52 PM ----------



I do have heated rear seats. I have a 2011 so if its been happening since 2007 I would think I have the update but who knows. Do you have a TSB reference. If I mention this to my dealer without giving them a TSB number I'll just get a lights on nobody home look.

I used a test light and tested the lug on the starter. This was the lug on the pasenger side. This lug had power when the car was off and the other lug had nothing, that is how I determined what lug to use. So as I was in process I just wanted to see if the extra battery would start the car and nothing lit on the dash, maybe it has a diode in the system some how but I thought it would work?
Just thinking here, if I connected to the wrong lug the starter would run all the time and not be able to shut it off. The other thing that has me scratching my head is the extra battery was 12.something volts and the other battery was about the same. But when I started the car they were both charger at 14.8v as they should. One of them is still the old battery, but it never had any problem starting the car, it was when I left something on and it drained quickly. This car also has the rear heated seats.

 

[SunlitComet]

Sorry about the missing digit but like i said it also could have been updated with later years My coverage only goes to 2010. anything newer then that i don't have so have them look for title no crank, no start, discharged or low battery. maybe something might come up.

 

[HOE-N-IT]

I used a test light and tested the lug on the starter. This was the lug on the pasenger side. This lug had power when the car was off and the other lug had nothing, that is how I determined what lug to use. So as I was in process I just wanted to see if the extra battery would start the car and nothing lit on the dash, maybe it has a diode in the system some how but I thought it would work?
Just thinking here, if I connected to the wrong lug the starter would run all the time and not be able to shut it off. The other thing that has me scratching my head is the extra battery was 12.something volts and the other battery was about the same. But when I started the car they were both charger at 14.8v as they should. One of them is still the old battery, but it never had any problem starting the car, it was when I left something on and it drained quickly. This car also has the rear heated seats.

Yes from what you say you have it wired correctly. It would not be getting charging voltage if not.

I did disconnect the negative from my main battery a few minutes ago and I still got all lights and the vehicle started and still with a very strong crank. There is a sensor in the negative cable from the main battery. It looks like a magnetic probe that circles the cable like on a clamp meter that measures current flow but I'm not sure how it is used. Mine still started with this negative cable disconnected.

While not related, it is best when wiring two batteries in parallel to have both batteries of the exact same size, model and age. You can google search for more information on this.

 

[02Lightning]

Yes from what you say you have it wired correctly. It would not be getting charging voltage if not.

I did disconnect the negative from my main battery a few minutes ago and I still got all lights and the vehicle started and still with a very strong crank. There is a sensor in the negative cable from the main battery. It looks like a magnetic probe that circles the cable like on a clamp meter that measures current flow but I'm not sure how it is used. Mine still started with this negative cable disconnected.

While not related, it is best when wiring two batteries in parallel to have both batteries of the exact same size, model and age. You can google search for more information on this.

I had the pos. disconnected on my main battery, I'll try disconnecting the neg. on the main battery and see what that does. Thanks, I do a google search on that also.

---------- Post added at 03:35 PM ---------- Previous post was at 03:17 PM ----------

Ok, just tried disconnecting the neg. on the main battery and everything was dead. Motor would not crank, no lights, nothing. I'm not totally convinced this dual battery thing is helping me.

 

[HOE-N-IT]

I had the pos. disconnected on my main battery, I'll try disconnecting the neg. on the main battery and see what that does. Thanks, I do a google search on that also.

---------- Post added at 03:35 PM ---------- Previous post was at 03:17 PM ----------

Ok, just tried disconnecting the neg. on the main battery and everything was dead. Motor would not crank, no lights, nothing. I'm not totally convinced this dual battery thing is helping me.

I checked a GM parts site and searched on the positive cable part number and it did list an 08 Denali as a application for this cable. The only thing I can suggest is disconnect your main battery and starting at the second battery use a multimeter to see how far you get and still get voltage.

You can also disconnect the positive on the second battery and place a meter between the positive post and cable and have someone start the vehicle and check to see if you get current draw. Did you connect the negative directly to the motor?

 

[02Lightning]

You know, it must be pulling from the 2nd battery because I did put the meter on the 2nd battery (not disconnected) and started the car and it pulled it down to 11v. while starting and then went to 14.8 charging. I do also have the neg. connected to the head on the motor. I guess I should be satisfied with that, it must have a diode in the system only letting the current go one way. I also found a picture of the starter and I do have it on the correct lug (just double checking myself again) because the other lug has a wire connected to it that goes into the starter. Thanks for your help Mike and everyone else, I may as well get another battery to match the first battery I just bought. I'd be pissed it the old one screwed the new one up.

 

[HOE-N-IT]

You know, it must be pulling from the 2nd battery because I did put the meter on the 2nd battery (not disconnected) and started the car and it pulled it down to 11v. while starting and then went to 14.8 charging. I do also have the neg. connected to the head on the motor. I guess I should be satisfied with that, it must have a diode in the system only letting the current go one way. I also found a picture of the starter and I do have it on the correct lug (just double checking myself again) because the other lug has a wire connected to it that goes into the starter. Thanks for your help Mike and everyone else, I may as well get another battery to match the first battery I just bought. I'd be pissed it the old one screwed the new one up.

Pulling it down to 11 volts seems a little low especially with 2 batteries. Although batteries in parallel should equalize I would make sure the second battery is fully charged even if it was new. I think the computer will "disconnect" a battery if the voltage becomes to low which may be happening when you disconnect the main battery. It's not like the old days where a low battery will show up with dim lights etc. Just a thought.

 

[02Lightning]

They are both fully charged, It may also be the old battery pulling the two down. I'm gong to buy a matching battery like the one I put in a week ago and be done with it.