Any ideas as to what is happening

[phillipmh06]

I've replaced the battery and the alternator both were bad. It's not my car. It's a 2004 Tahoe LT completely loaded.

Sent from my SM-N960U using Tapatalk

 

[Doubeleive]

I've replaced the battery and the alternator both were bad. It's not my car. It's a 2004 Tahoe LT completely loaded.

Sent from my SM-N960U using Tapatalk

most likely it is a sensor, like a shock sensor, ride height or possibly a abs sensor, even could be a mild engine related issue or transmission issue a tech2 scan will tell you exactly what it is, or any other HIGH end scanner like a snap on or matco
your basic low or mid grade scanner will not tell you what it is.

 

[Doubeleive]

and you posted in the wrong section, you may want to move this to the nbs section @yates ™ ,

 

[phillipmh06]

When this happens none of the gauges work but the tach and speedo. Throws all kinds of lights and codes. I have a solid edge. I'll try to get more info. Hard to do when you work in HVAC this time of year plus it's not my vehicle. Just trying to help a friend out.

Sent from my SM-N960U using Tapatalk

 

[Fless]

I'd start by checking the battery cables and cleaning those contacts and the main grounds. Clean them, not just check them. Take apart the connections, clean the terminals, flex the battery cables to see if they're weak, etc.

 

[iamdub]

I second what @Fless said.