Need assistance with 2011 Yukon- power failure

[Kyzrsoze]

I found this post on another forum:

Don't pay huge money for diagnostics...please read!!!! I finally found someone that fixed my Yukon XL and fixed it right...The problem is the ground wires. My mechanic tightened one that he found loose and the other one the clamp was messed up so the ground wire was flopping around and not making a good connection. When he touched the ground wire he could hear the fuel pump going on and off and other things making noises. It was a $3 dollar clamp that fixed it...too bad I spent almost $2000 on diagnostics with the dealership that was trying to tell me I had a bad transfer case module as well as a bunch of other BS and another mechanic before I brought it to this guy. Make sure your mechanic checks all the grounds (I didn't know that there's more than one) and tightens them as well as making sure the clamps are in good condition. My clamp was broken causing a bad connection. So...it's a $3 part that caused this hellified problem! I'm just glad to have my vehicle back in good running condition...no thanks to the dealership or GMC!

 

[mo mauser]

I replaced the battery after work yesterday. I noticed a significantly more consistent reading on the volt gauge than that morning so that is encouraging. I'm thinking of checking the grounds as that's a rather easy next step. Thanks

 

[Kyzrsoze]

I replaced the battery after work yesterday. I noticed a significantly more consistent reading on the volt gauge than that morning so that is encouraging. I'm thinking of checking the grounds as that's a rather easy next step. Thanks

Keep in mind that the battery's main job is to provide power to some items when the the inginition switch is on and to power the starter. The alternator takes over all electrical functions when the engine is running. If the alternator is weak or if the power isn't getting through because of a bad connection the battery will take over and power everything - until it runs low and things start shutting off. I guess what I'm saying is that if the new battery makes things better with the car running, that indicates problem somewhere else.

 

[Plinker66]

It’s my understanding that the alternator doesn’t power the car when it’s idling.

If you experience sudden loss of electrical power when idling there is prolly a faulty connection from the battery.

My bad battery bolt twisted up pretty tight, even when it was worn out. I had to figure it out by jiggling the battery bolt after I lost power.

 

[Kyzrsoze]

It’s my understanding that the alternator doesn’t power the car when it’s idling.

I'll double check, but I don't believe that's right. One of the ways you test for a bad alternator is to start the car and then unhook the battery. A car should run with no battery once started. The alternator should run all electrical functions and charge the battery. If the car dies when the battery is disconnected you definitely have a bad alternator.

Sent from my Moto G (4) using Tapatalk

 

[Plinker66]

...If the car dies when the battery is disconnected you definitely have a bad alternator.

Sent from my Moto G (4) using Tapatalk

My Yukon xl died while standing idling about five times.

I changed the worn stripped battery bolt, that’s all. Now it runs fine.

If the battery isn’t necessary, how can your statement be correct?

 

[harrycalahan]

My Yukon xl died while standing idling about five times.

I changed the worn stripped battery bolt, that’s all. Now it runs fine.

If the battery isn’t necessary, how can your statement be correct?

That just means you were drawing more power than the Alt could produce at idle. Alt’s do supply power at idle. But not the full amperage until the rpms increase.

 

[Plinker66]

That just means you were drawing more power than the Alt could produce at idle. Alt’s do supply power at idle. But not the full amperage until the rpms increase.

...well that seems like you are saying is that my Yukon alternator won’t run my old Yukon at idle without the battery... but it’s still good enough to charge my battery? ... Kyzrsoze ?

 

[harrycalahan]

...well that seems like you are saying is that my Yukon alternator won’t run my old Yukon at idle without the battery... but it’s still good enough to charge my battery? ... Kyzrsoze ?

Takes a lot of juice to thump those woofers in the back.

 

[Kyzrsoze]

My Yukon xl died while standing idling about five times.

I changed the worn stripped battery bolt, that’s all. Now it runs fine.

If the battery isn’t necessary, how can your statement be correct?

It could mean that you have a weak alternator and at idle your battery is carrying some of the load. With that bad bolt /connection you lost part of your power source and it died.

I don't think the battery is typically getting much of a charge at idle even when things are working properly, but at driving speed/rpm your alternator is putting out enough to get the job done. If yours is weak or failing it may be working well enough at driving speed to charge the battery and run everything, but at idle it isn't working at 100%.

Just guesses though. Electricity is weird.

By the way, I'm recovering from knee surgery and on strong meds today, so I may not make any sense at all.