Under dash module question


85 Triple Threat
Im pretty sure that I have a bad factory security module as my factory alarm does not work anymore. I was told it is the black box that is above the parking brake release. I have found the little black box, but my question is, that there is also a little white module box attached to the security module box, is it part of the security feature as well. No one ever mentioned a white module as well so I wasnt sure. I looked in my other GN that does not have the factory alarm and it doesnt have the little white box. I do have a digital dash in the car with the alarm so I wasnt sure if it was part of that or not? Any help is appreciated. Thanks Dusty