ave a 2002 Tahoe, 5.3, 4x4. The battery light keeps coming on and going off sporadically. At the same time it comes on, my speedometer and fuel gauge stop working and all icons on my cluster pop on. Then they go off again, and everything works. I just put a brand new battery in. Occasionally, when I attempt to start it, the truck is completely dead. It's is also has a rough start now as if it has a cough. It is running very rough like it doesn't have power and feels like it wants to shut down. Also, when the cluster goes crazy, and if I'm using the A/C, the air blowing starts to feel warm. I also had an issue the other day, for the 1st time. When I was turning the truck off, the key wouldn't turn all the way back. The truck turned off, the battery light stayed on and I was still able to take the key out. I wiggled the steering wheel a little and it finally turned all the way off and the battery light went out. If anyone can get me on the right track, I'd appreciate it. Thanks n advance.

 

have your electrical system (batt + alternator) load tested.
Make sure you all your electrical connections are clean and tight (battery, ground, etc.)
Check for janky ignition switch.
Check for parasitic drain