2018 gmc Yukon slt having electrical issues

[2018yd]

I have a 2018 Yukon slt with about 76k miles and it’s currently having electrical issues. I have to press the start button about 3 times before it turns on and when it does it says to service all the safety features like theft deterrent system, airbags, blind spot, safety restraint, front camera, ACC, lane keep assist, steering column lock etc. the interior lights also dim down and get bright, kind of like in a pulsing way. The dash is also showing everything on zero, I’ve replaced the battery and both key fob batteries and nothing has worked. Was wondering if anyone else has had this issue or if anyone knows how to fix it. If you have suggestions on what it might be, tell me, please and thank you.

 

[Fless]

I would suggest having the charging system checked (including measuring the Alternating Current value on the alternator output), and checking and cleaning the main engine and body grounds.

A positive or negative battery cable that's rotted from the inside could also be causing this issue.

 

[RoadTrip]

Bad battery cables — particularly the ground cable — is a known issue with these vehicles that cause strange electrical issues.

Also check to make sure the ground from the rear of the engine block to the body is still attached and corrosion free.

Seems weird that battery cables can corrode from the inside, but when they started doing the stamped terminal designs, we no longer can tell their condition.

 

[BlaineBug]

I have a 2018 Yukon slt with about 76k miles and it’s currently having electrical issues. I have to press the start button about 3 times before it turns on and when it does it says to service all the safety features like theft deterrent system, airbags, blind spot, safety restraint, front camera, ACC, lane keep assist, steering column lock etc. the interior lights also dim down and get bright, kind of like in a pulsing way. The dash is also showing everything on zero, I’ve replaced the battery and both key fob batteries and nothing has worked. Was wondering if anyone else has had this issue or if anyone knows how to fix it. If you have suggestions on what it might be, tell me, please and thank you.

Check your main battery ground on the passenger side frame rail behind the cloth/plush/whatever fender liner, remove and clean and reinstall. Very easy to access especially with the wheel removed. If that checks OK, you may want to investigate ground point G218 in the dashboard;