Intermittent Electrical Issue

[PJDYukonXL]

I drove my 16 Yukon XL 5.3 two nights ago and noticed it starting sluggishly. I had a number of errands to run and it seemed to get worse every time. I left the vehicle running as I went in the store on my last errand in fear the vehicle wouldn't start again. In the way home I stopped at the auto parts store where they tested the battery and it was good.

Truck started right up afterwards, no problem. I drove home and forgot about the issue. Last night I go to start the truck and it just clicks like the battery is completely dead. I try a couple of times and nothing. Left it over night to deal with today.

This morning it starts up, sluggishly again and then says its set to memory 2 and all my presets on the radio are gone.

I've checked the terminal connections and they all seem to be good. I'm wondering if it's a bad cable/ground?

Does anyone have an image or file showing all the ground connections/locations to check?

If anyone has other ideas, let me know! Thank you in advance!

 

[wjburken]

Might get your alternator checked as well.

 

[Big Mama]

Welcome to the forum from Virginia. Does sound like a ground issue but electrical problems can come from lots of places. Do you know if they load tested the battery? If you have a multimeter check battery voltage before starting and after.

 

[PJDYukonXL]

Welcome to the forum from Virginia. Does sound like a ground issue but electrical problems can come from lots of places. Do you know if they load tested the battery? If you have a multimeter check battery voltage before starting and after.

Before: 12.8
Running: 15.2 initially then down to 14.5 and held around 14.7

 

[Big Mama]

Sounds like the battery and alternator are working well, which leaves the ground cables, battery cables, and the starter though it would be rare for one to go bad that soon.

 

[PJDYukonXL]

Update: Took it to another shop that specializes in electrical systems... they load tested the battery and determined there was a bad cell. Replaced battery and all is good now!

 

[91RS]

The battery cables are absolute garbage on these. The negative and the short positive cable on top of the battery. I would go ahead and replace them even with the new battery.

 

[DenaliBQ]

the ac delco batteries are known for dead cells on the 16s and other trucks

 

[Big Mama]

Update: Took it to another shop that specializes in electrical systems... they load tested the battery and determined there was a bad cell. Replaced battery and all is good now!

that’s great. Thanks for closing the loop for the next guy

 

[Jason in DLH]

Welcome to the forum from Virginia. Does sound like a ground issue but electrical problems can come from lots of places. Do you know if they load tested the battery? If you have a multimeter check battery voltage before starting and after.

True this. My radio and lights were acting strangely for the longest time and simply couldn’t figure out why. Problem seems to have been fixed after I replaced my cracked and corroded front impact sensors as it’s going on a few weeks without issues.