Anyone have any idea why this light would be coming on. 2011 1500 5.7. It doesn't come on all the time but it comes on when I start the pu and stays on. The charging gauge shows that it's discharging a little. But what would cause this?

 

I think the light comes on when you start the pickup because the battery is weak or the starter is drawing too much current. When you start the truck, the battery voltage is dipping below a certain level and the truck is flagging it. Take the truck and have the charging system checked out and the battery tested.

 

Check the serpentine belt (fan belt), it may be stretched from wear and slipping on startup.

 

An update to my charging problem. Truck has around 35k on and never had any issues. It turns out that the hot wire going to the alternator wasn't making a good connection. When I was checking things out trying to figure out what it was I had the truck running and I reached down and felt the connection. It was fire hot where it bolts to the alternator. I knew that shouldn't be hot like that so killed the engine and put a socket on the nut. I tried to losen and tighten but it really didn't move. But,my battery light did go off so I guess it must have moved enough to make a better connection. It was tight enough that I couldn't break it lose without fear of breaking the stud off. Pretty weird deal.

 

You've got a bad alternator. Basically, the alternator is trying to charge the battery thru that wire but it has (had) high resistance, thus the heat. Sounds like there is something loose inside the casing.

 

Could be but it's charging fine now. I will keep an eye on it in the future. Might pick up a spare and put it in the tool box. Ya never know...