If you want to definitively rule out the adapter as the source of the problem, try it on another Dell laptop to see if it is recognized in BIOS. Charging issues indicate generally indicate a fault with at least one of three items (if not the battery): It's a process of elimination to figure out where the problem lies, or at least where it doesn't lie. For example, if your AC adapter is recognized and works on another Dell laptop, then the problem is likely your charging jack or charging circuit. Check if the light is lit at the plug end of the AC adapter or on the adapter block. And see if that light remains lit when you plug it into the laptop's jack. If the AC adapter's light goes dark when you plug it into the laptop, then the fault is likely with the jack or the circuit.  Hold F2 while booting, to enter BIOS. See if the AC adapter is recognized. Try another genuine Dell AC adapter of at least the same wattage/amperage. If that second Dell AC adapter works and is recognized in BIOS, then the fault is likely with your AC adapter. If it doesn't work, then the fault is likely with the jack or the circuit. The jack is a relatively inexpensive item that is not difficult to replace for someone experienced in working on laptops. If a good AC adapter and a new jack won't work, then the fault is likely with the charging circuit on the motherboard, which would normally require replacement of the motherboard. Also, it's worth trying a reset: There is a centre pin in the adapter's plug (the end that connects to your laptop's jack/port). If that centre pin is broken or bent, then that is the cause. If it's bent, you could try gently to straighten it. If it's not bent, clean out the connector with Q-tip and 99% alcohol, and do the same to the jack. Try slightly moving/jiggling the plug in the jack: if the light goes out or charging stops, then the problem is the charging jack or the pin in the plug. Run Dell Diagnostics:Press and hold F12 while booting to enter the One Time Boot Menu, select Diagnostics and press Enter. The Dell Diagnostics will test major hardware components. Choose to run extended tests. Since you already tried another adapter and changed the charging jack, evidence suggests that the fault is on the motherboard. However, I like to be thorough, so try what I suggested to definitively narrow down the source of the problem.
My warranty expired in November 2022 and my laptop has been having trouble charging lately. I've run tests and checked the battery and through support assist, the battery health is "good". Though, when I run hardware tests on Dell.com, I get a "warning" result saying the battery's capacity is decreased. Obviously, "good" is a decreased capacity from "excellent", though not enough of an issue to warrant a new battery. Here's what happens: I plug in the charger, the charging light turns on for two seconds, then turns off and the icon says "X% available (plugged in)" but the computer does not charge. I conducted a charger test and the test reported that the charger failed. I ordered a replacement charger from Dell and the same issue happened, so I sent it back. I ordered a USB-C charger and the computer is charging fine using that. I could stop here, but now I can't use my USB-C port to connect to my external monitor (and even with the battery capacity at "good", it only lasts for about an hour until I need to plug in - which is fine, I'm usually near an outlet). I also tried replacing the charging port, but that didn't make a difference, so I put the original back in.  I understand that this seems like an issue with the charger but if it is, why would a replacement charger from Dell have the same issue? If it's an issue with the charging port, is there a way to test that hardware? I ran the "Full Test" that takes 40 minutes and the only issue that came up was the slightly decreased battery capacity. It's possible that the replacement charger I got from Dell was a dud and I should try ordering again but wanted to crowdsource thoughts first.  Thanks in advance!
XPS 15 9579 issue with charger, charging port, or battery?