What is this relay and wires??? Also need a rectangular plug

[steveo3318]

Ok here are some pictures of some wires I found discretely tucked away behind the fender-well today. They were taped up and not hooked to anything. The relay looking box only has two prongs. A dark blue wire and a brown with yellow or white stripe, and the larger red wire. the relay looking box is kind of behind the hood spring! Absolutely everything in the truck electronically works. I cant figure this one out? Also whats the rectangular plug called that goes right under the accelerator. I can't find it in LMC for the life of me. I have my whole firewall plugged now except that.