Voltage regulator question

[69GT 0]

So I went in to replace the voltage regulator on the car because ive been getting some high spikes and there are some wires missing. I attached 2 pictures below but one of the things missing is comming off a yellow wire. The other is black and looks like something plugs into it but I have no idea what.

 

Im guessing the small thing is a condensor of some sort? Could that maybe be why im getting voltage spikes? I would appreciate any info someone could give me.

 

Edit: Looks like I found what they are and where they go to. Yellow goes to the hacked/broken off radio condensor and the other one is Violet which goes to the dash panel. Does that one control the alt. gauge inside the car by chance? It would explain why its never worked before..