I have an 01 Chevy Suburban 4x4 and for some reason my battery keeps dying sometimes while driving it. I get a jump and it starts right away and will drive for a time before it goes bad. I was first told it was my ignition cluster, had it installed but battery still kept dying. Took it to the dealership they said replace ECM/PCM, did that had it flashed and my battery still keeps dying. I was told it could be my ECM/PCM relay. I'm out of ideas and don't know where else to take it for repair or at least a proper diagnosis.

 

the vehicle has to be checked for a parasitic draw. If excessive, over 50mAmps, the source of the draw must be isolated.
eric the car guy has a nice video on tracing draws...search for his channel.

 

What I don't "get" is the sometimes the battery dies while driving. This has a voltmeter in dash? I'd suggest monitor that, and with that counter check it with a VOM. Monitor the volt meter while driving. It should stay steady at 13.5-14 volts regardless of the speed/rpm

 

oh...missed that...ignore my post.