Spa Side remote?

Good day to all. I am a new member and would have tried a search first, but I'm apparently unable to so that yet! My son and his family just bought a new home with a pool in SO. Cal. I've had a spa forever, but I'm not familiar with all the pool equipment. It's a standard pool/spa setup with Aqualink Control pwer center and one touch controller in the house. His remote (wired) spa switch does not work. I have the Aqualink power center manual and see where the spa side switch is suppose to connect via a 6 terminal brown connector. However, there is no connector attached. I found a cable inside the box that is un-connected and has no connector attached to the wires. Most confusing is the fact that there are only 3 wires in the cable! Red, Blk and blue?

My first thought is to pry the spa side switch away from the spa wall and pull on the wire to see if the one in the box is the one coming from the spa side switch? If so, there should clearly be 5 or 6 wires?

Also, I can not find anything that says which terminals on the brown connector control which functions so I can manually test the PCB connector to see if a new switch would actually work!

Again, thanx for any comments!