Dometic Americana Power

I took a chance on the lower circuit board being faulty and ordered a Dinosaur Exact Replacement. All of the existing wires clipped right up to the new board. However, I do have a question about an electronic device that was glued to the cover of the original black box cover. It has three wires; red (goes up the back to the upper board?), blue to a independent round device , and black to ground. What is this rectangular thing? A new one did not come secured to the new Dinosaur cover box and there were no installation instructions. Am I correct to assume that I need to re-connect this as it was previously. I just want to be careful and not burn up this new purchase.

I was going to attach a few pics, but I don't see way to do it. Prior assistance is appreciated and I will be grateful for further advice.