Did you learn the answer to your question? I'm having the same issue -- I keep pressing the gold button but the battery light stays on.

Does anyone know exactly which 2015 Retina MacBook models this applies to? All of them? I'm applying 5W to mine after repair and not getting a chime.

I completed this guide without incident, but plugging in to the 5V/1A charger didn't give me a chime. (I left it plugged in to that overnight just in case.) When I reassembled, screwing in the screw in step 12 turned on the faint white LED, which I understood to mean that the new battery was making good contact. The ribbon cable from the USB-C port also seemed to click back in place with no issues. I plan to disassemble and check both of these again (along with the grounding clip), does anyone else have any more suggestions for things to check when I open it back up? I'm handy with a multimeter if that helps.

Thank you Stuart! I would never have thought of this and it worked perfectly.