THIS DOES NOT APPLY TO BOSCH STARTER SOLENOIDS. This only applies to *some* Magneti Marelli starter solenoids. If your Magneti Marelli starter solenoid has two 5 mm terminals, one will be for the thick red wire from the starter relay. The other will be for a ground wire. The easiest solution is to ground the solenoid to the body of the starter, as shown in the photos below.