Thanks for the reply.
To clarify, my original motor control board has a straight 6 pin connector, 3 pins used for the incline sensor, and 3 pins for the speed sensor. The new, most likely el cheapo, "universal" Aliexpress replacement board I thought I'd take a shot at has two separate 3 pin connectors for each function as shown above.
I was able to cut the original 6 pin connector in half and use it as is for the incline, luckily the Vcc, -, and O lined up exactly, and the connector just fit securely after I shaved off some plastic. Despite the well written notes on the picture above "Note: speed sensor not need to connect", I wanted to connect it because it was there. However, for the speed sensor, the wiring did not line up, and I butchered the connector pretty bad trying to get the metal connectors out of the plastic housing (plastic was brittle and falling apart), so I just ended up splicing in dupont connectors, and hot glued to attach and secure them in place. I was just looking for a cleaner solution to find a way to buy these 3 pin connectors in a kit, and that someone on this forum might recognize the socket name and be able to rattle off what it's called. But no need now.
It's a 20 year old treadmill with what appears to be some very stout motors, at least they appear to be overbuilt from what they put in treadmills today. So, revived for now, wife is happy, I'm happy, and I saved some landfill waste for a few more years, or longer, hopefully.