I HAVE A 92 RS MARO WITH TBI. IT HAS A WHAT LOOKS TO BE A SMALL GROUND BLOCK WITH WIRES GOING TO NEXT TO THE RADIATOR. WHAT IS THIS BOX FOR? WILL IT AFFECT HOW THE CAR PERFORMS? WILL IT CHANGE IDLE? ALSO WILL IT LEAD TO A LOW VOLTAGE READING ON THE VOLTMETER? PLEASE HELP. I LOOK AT IT THIS MORNING AND SAW A WIRE DISCONNECTED FROM THERE. BUT ALL THE CABLES THAT GO THERE LOOKED TO BE JERRY RIGGED

 

Hard to tell from your description, but a picture may help.

 

check to see if there is ANY corosion on the wires. if there is, cut them ends and replace them. cut back untill you cant see any corosion anymore if you can, if not, you may need to replace the wire. but yes, that MAY lead to a low voltage reading, it happened to me.