Denali won't start after short time with key off but radio/ and or interior lights left on

[leopold]

Hello Everyone,

This is my first post here. I have done a bit of cruising in this forum but not a lot. I have a 2007 Denali that is giving me fits occasionally. Yesterday when I stopped to get gas, I left the radio on as my family was in the vehicle. When I got back in to leave the truck would not start. This is the third or fourth time it has done this with either the radio or the interior lights were left on. None of the occasions was a long time. I know the system has an automatic shut off after a certain amount of time to prevent a battery drain but it should start easily if it had hit that timeout switch. In each occasion the vehicle needed to be jumped to get it started. The last time it happened I brought it to NAPA to have them test the battery. The battery tested fine. He did indicate it seemed it was only not fully charging, but battery capacity was good. (if that makes sense. I'm not very mechanically inclined but trying to learn).

The positive post does has some crud on it which I cleaned as best I could the last time this happened. It is difficult to get positive post off the battery because of the weir wiring harness IMO. Is this a cable issue or is there a short somewhere?

I am looking for some direction or other posts to read about this if anyone knows of any before I bring it somewhere.

 

[kbuskill]

I would mix up baking soda and water and clean both posts with a toothbrush.

Next time it does this try moving the battery cables around.

These trucks are known to get corrosion inside the cables.

 

[swathdiver]

If the cables are good it could still be the battery. How old is the battery and what brand/kind is it?

 

[leopold]

If the cables are good it could still be the battery. How old is the battery and what brand/kind is it?

I cannot get the positive cable off. There is some crud I can clean them for sure. It makes me curious though why it is only doing it after the radio has been left on or the lights for a few minutes. In this case, the time it took to fill the gas tank. That's not enough time to drain the battery imo.

 

[Doubeleive]

I cannot get the positive cable off. There is some crud I can clean them for sure. It makes me curious though why it is only doing it after the radio has been left on or the lights for a few minutes. In this case, the time it took to fill the gas tank. That's not enough time to drain the battery imo.

grab the positive post with some big channel locks and twist, it will come off, if cleaning up the cables/ground does not work you may need new cables, but I would be leaning more towards replacing the battery, get yourself a good AGM if you can there much more dependable.

 

[Big Mama]

The computers in your truck, I have the same one, protect themselves at all cost. Once power is close to not feeding them everything stops. I’d say it sounds like a connection problem so check both ends of both cables.

 

[Tonyrodz]

I'd swap out the battery.

 

[Scottydoggs]

if your not fully charged, its either a bad connection, either loose or corroded terminal. or a bad alternator.

at the parts store they should be testing for volts engine off, you want to see 12 volts. then load test it, then fire up the truck and test its voltage once again. you should see 13+ volts running as the alt charges. if the alts not past 12 or under, the alt is bad.

if it fails the load test, just get a new battery. they only last 5 years tops. theres a date on the battery and the months its rated to last for.

id have it retested after taking off and cleaning both battery terminals. they sell a wire brush cleaner, terminals are lead, so you can get them to shine back up pretty easy at the contact points. hell scrapping them clean with a sharp razor works too. you know if in a pinch to get it done.

try not to breath in any dust that comes off the terminals. it tastes bad and cant be good for you.

 

[Tonyrodz]

if your not fully charged, its either a bad connection, either loose or corroded terminal. or a bad alternator.

at the parts store they should be testing for volts engine off, you want to see 12 volts. then load test it, then fire up the truck and test its voltage once again. you should see 13+ volts running as the alt charges. if the alts not past 12 or under, the alt is bad.

if it fails the load test, just get a new battery. they only last 5 years tops. theres a date on the battery and the months its rated to last for.

id have it retested after taking off and cleaning both battery terminals. they sell a wire brush cleaner, terminals are lead, so you can get them to shine back up pretty easy at the contact points. hell scrapping them clean with a sharp razor works too. you know if in a pinch to get it done.

try not to breath in any dust that comes off the terminals. it tastes bad and cant be good for you.

You're not supposed to do a taste test!

 

[Scottydoggs]

You're not supposed to do a taste test!

well i pretty much posted one of my own f ups from back in the day.

another good time.

ever taste battery acid? i dropped a battery, it broke shot acid up my leg and then chest to face, yes it got im my mouth. nasty crap. i had to toss out everything i was wearing, acid burned holes in all of it.

 

[Big Mama]

One thing I forgot and didn’t see. The radio has two options for staying on. If you turn off ignition it stops when door opens. If you leave key in acc the radio doesn’t have a time limit that I know of other than voltage dropping then it turns itself off. I think you mentioned leaving radio on while getting gas. If it turned off low voltage not time was why? Fellas is that correct?