MacBook Pro, Late 2016 Function Keys, Battery not Recognized

Today I attempted to replace the SSD of my MacBook Pro (13’, late 2016, function keys). The machine had no problems before this procedure.

I opened the case, disconnected one end of the battery daughter board test cable (although I did so accidentally at first when trying to remove the screw), removed the silver screw, lifted the bridge, changed the ssd, then did everything in reverse. I then booted to an external hard drive to install OSX. I noticed that I could only boot with the power cable plugged in. The new drive was not recognized. even when I used the diskutil utility in terminal.

Given these issues, I put the old SSD back in. Now I am having many issues with the machine. I have a feeling that I inadvertently damaged the daughter board test cable during my installation.

Current Issues:

Macbook won’t start up unless I have BOTH the power cable AND the external drive plugged in.

After a shutdown, if I try to startup the machine immediately shuts down. If I try again, it starts up. Once started up, I notice that the battery is not recognized (says DNL in battery condition under system preferences, system information says no battery connected, coconutbattery sees no battery).

I have tried resetting the PRAM and VRAM and resetting the SMC to no avail.

The one clue I have is that when I started up the machine with the lower casing off and unplugged the battery daughter board test cable (while everything was on), for a moment the battery indicator turned on and said 75% (which I think was the percentage it had previously). Combined with the fact that I did not use extreme care when I first removed the battery daughter board test cable, I would guess that I damaged it during my installation.

While most of this would make sense given a bad battery connector, I don’t get why I wouldn’t be able to start the computer without the external drive plugged in, and why I it shuts down (wouldn’t it just work without the battery?!) Secondly, when I visually inspect the components, there is no apparent damage.

I’m ordering a replacement battery daughter board test cable (https://www.amazon.com/gp/product/B07YXP...). Once it arrives, I’ll let you know if replacing it fixes anything. In the meantime, I love to hear any ideas.

Thanks!

EDIT: Replacing the battery daughter board test cable fixed my battery issue. Now I can return to replacing my SSD.