Please correct me if I am wrong!!!
The #3 and #6 pins are the same thing.
The #4 and #5 pins are the same also. Putting a load on 6 is the same as putting it on 3 while applying power to 4 or 5.
I would agree that that is what it looks like. However, that is a 16 amp relay. It may be that there are two pins in order to spread the load so that for example pin 3 isn't carrying the full 16A. If you connected the load to BOTH 3 AND 6, they would share the 16 amps.
Fortunately, I won't have 16A running through it. At most, I might see 1.5A for devices associated to an aquarium.
But, it is the style I need to do what I want to accomplish.
Now, I just have to figure out why I get garbage on a serial3 from the Due to the ESP32. It does it after about 3 days of up time.
Thanks for the reply.