Grand Cherokee 2WD V6-3.7L (2008)
Starter Relay: Description and Operation
Operation
OPERATION
The ISO relay consists of an electromagnetic coil, a resistor 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.
