My 01 suburban was having to be jumped every time I started it, if I did not immediately take the keys out and exit the vehicle. If I just parked and turned the truck off it would drain the battery. I got a new battery and now it won't start without being jumped. Battery is at 12v when off, 14v when running. When I try to start it the lights are dim and flicker. When I hook it up to the other truck it starts fine but seems like it may have a miss when it is running. I have a check ride control and check abs light on too. Is this a bad body ground? Bad relay(s)? Bad alternator? Or another issue I'm missing? Any help and advice is appreciated. Thanks on advance.

 

I would first check to make sure the cables are clean and tight at each end and also check to see if has corrosion inside the insulation covering of the battery cables. That creates a lot of resistance to the flow of power to the starter and especially if are original cables. It does sound like you have a draw though. If you are not mechanically inclined I would have a trusted friend or tech check for that. If you have a DVOM and know what you are doing, then read on. The best place to always start when looking for a draw is to have your DVOM hooked up and monitor what the draw is and then unplug the alternator. The diodes in there can go bad causing a draw and that is an easy place to start. It can still charge the battery correctly but have a bad diode. Next you start unplugging fuses and relays to check to see when the draw goes away. The box under the hood and the fuse box under the drivers side dash or at the drivers side end of dash with a cover there. When you find the culprit, make sure you check all items ran by that fuse/relay. Many times the fuse will control several items. There is also power block under the vehicle along the frame area near the back to look at. It is more of a power junction block but should be checked. You should also read this, especially if you are in a rust belt state:

https://www.fixmyoldride.com/Chevrol...pos=3&at_tot=4