Welcome back:
You should get the BCM recall taken care of, but I don't think that is the problem. No matter if the battery is charged or you add the booster, 12 volts is just 12 volts. You have a connection issue. Since it works with the jumper connected but not without, I suspect there is a problem right where you are attaching the booster, the battery. Remove the battery cables and properly clean both the battery terminals as well as the cable terminals. When you replace them, make sure they are tight. Interestingly, I have seen this many times in the past. The key is turned on and all lights indicate everything is fine until you try to crank it. When that is done, the extreme load on the terminals allows it to fail and shuts power down to everything. Also, when you attach the booster, the clamps on the booster cables tighten the battery terminals enough to make contact and start the engine.
I hope that made sense. I feel like I said the words battery and booster a hundred times.
Anyway, it happens enough that we have a link that discusses it. Take a look through it.
https://www.2carpros.com/articles/everything-goes-dead-when-engine-is-cranked
Just for the heck of it, try what is indicated in the link. Let me know the results.
Take care,
Joe
Friday, January 29th, 2021 AT 9:54 AM