hey im rewiring my 86 t/a to tpi set up,its getting there but, from the tpi harness, there is the brown/white wire going to check engine light, but the connector on the car harness has at this spot,a white/green wire?? going to a blue plastic box,along with a ground,a pink 12 v and it exits the box in a yellow wire going to the clusters,,,, anyone knows what that is? could this be my check engine light? i dont have a brown /white comming out of my harness,although there are a few just brown,does anyone know what that blue box is? and what is the yellow wire for,,,and if its not for check light,,,where does it go