Starter Motor Relay
WARNING: This page is about a different car, the 2004 Dodge Pickup, 2004 Dodge Cab & Chassis, 2003 Dodge Pickup, and 2003 Dodge Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
The ISO relay consists of an electromagnetic coil, a resister or diode, and three (two fixed and one movable) electrical contacts. The movable (common feed) relay contact is held against one of the fixed contacts (normally closed) by spring pressure. When electromagnetic coil is energized, it draws the movable contact away from normally closed fixed contact, and holds it against the other (normally open) fixed contact.
When electromagnetic coil is de-energized, spring pressure returns movable contact to normally closed position. The resistor or diode is connected in parallel with electromagnetic coil within relay, and helps to dissipate voltage spikes produced when coil is de-energized.