2017 Yukon XL SLT Dash says Charging problems and everything goes nuts

[Datruckdriver]

I have a 2017 Yukon XL SLT. I bought it around mid- Jan of this year. I put a new alternator on it within the first month. Today, I leave work, and alarms start going off saying service charging system. The truck starts shutting off all “non essential “ functions and then dies. I got a jump, and barely made it back to work. I mean this thing Cut off power steering, EVERYTHING! Anyone Know whAt the issue could be? Please? I’m already overpaying for this truck and the warranty from Alpha 1 is garbage. They have already denied 2 of my claims. Also, I replaced the alternator within a month of getting it from the dealership. Thanks for your help

 

[salisburyv]

you might need to replace the battery. but i would also check all the grounds. make sure all connections are tight. do you have a battery charger? some units can tell if the battery is bad. try that..

 

[Datruckdriver]

you might need to replace the battery. but i would also check all the grounds. make sure all connections are tight. do you have a battery charger? some units can tell if the battery is bad. try that..

I will check the grounds, I have the battery on 2amp charge overnight now. When I had it running, even if the battery was bad, shouldn’t the alternator (assuming it’s working properly) keep the truck running at least?

 

[OR VietVet]

Alternator is needed because battery cannot power it all. Why did you change the alternator to begin with? I suspect a faulty/poor quality/cheap alternator. Yes, check all grounds and cable connection cleanliness. Look under insulation at battery cables just off the battery.

 

[Datruckdriver]

Alternator was changed originally because it was not charging. Had it tested and it was bad. Put the new one on that I bought at one of the big name auto parts stores , hadn’t had a problem until today.

 

[swathdiver]

Get a GM OE alternator and if the battery is four or more years old replace that as well. Then look to get an advanced scan tool that can do a parasitic draw test and keep tabs on the health of the battery such as GMs MDI2 with GDS2 software on a laptop.

 

[Datruckdriver]

I am up underneath it as we speak, checking for loose ground wires. I have found a few but they are all snug or tight so far. I’ve got the one coming off the battery to the engine block, I found one underneath drivers door connected to body mount Bracket. I’m sure there’s probably about 100 more or I’m just slowly looking for them. I think I’ll take this alternator off before 7 AM and maybe I’ll get a chance to run it and get it checked out that should still be under warranty. I put a voltmeter on it this morning And it showed about 11 1/2 V. Then I started it, went from 13.5 V down to about 7 pretty rapidly

 

[OR VietVet]

Like @swathdiver said about battery and I said about the likelihood of a failing new alternator, I believe you have found the problem. I would still locate all grounds, many threads here about that causing numerous weird problems. Also, check for that corrosion.

 

[swathdiver]

I am up underneath it as we speak, checking for loose ground wires. I have found a few but they are all snug or tight so far. I’ve got the one coming off the battery to the engine block, I found one underneath drivers door connected to body mount Bracket. I’m sure there’s probably about 100 more or I’m just slowly looking for them. I think I’ll take this alternator off before 7 AM and maybe I’ll get a chance to run it and get it checked out that should still be under warranty. I put a voltmeter on it this morning And it showed about 11 1/2 V. Then I started it, went from 13.5 V down to about 7 pretty rapidly

A bad battery can take out an alternator and think that's what you discovered this AM. I would not care about the warranty, get a GM OE alternator and a new battery. I prefer the ACDelco Gold/Professional line but everyone has their favorites.

 

[OR VietVet]

Always been a big fan of Interstate batteries.

 

[salisburyv]

and just because the grounds are tight does not mean they're good. what color are they? is it a light blue/green? that's corrosion. it'll get between the ground points and render them less effective. I cleaned all the mounting surfaces, and then treated the area to reduce the chance of it happening again. super-lube anti-corrosion and connector gel. works pretty good. if you bought the alt recently they should exchange it without issue. let us know plz

 

[Tahoe14]

If you have not had your extended warranty that long you could cancel it, receive a refund and get a good one.

 

[sealandsky]

I am up underneath it as we speak, checking for loose ground wires. I have found a few but they are all snug or tight so far. I’ve got the one coming off the battery to the engine block, I found one underneath drivers door connected to body mount Bracket. I’m sure there’s probably about 100 more or I’m just slowly looking for them. I think I’ll take this alternator off before 7 AM and maybe I’ll get a chance to run it and get it checked out that should still be under warranty. I put a voltmeter on it this morning And it showed about 11 1/2 V. Then I started it, went from 13.5 V down to about 7 pretty rapidly

Don't just make sure the grounds are tight - Remove them, clean the contact area, then reinstall. Grounds are everything on these vehicles.