Intrepid V6-2.7L VIN R (2003)
Heated Glass Element Relay: Description and Operation
The rear window defogger relay is an electromechanical device that switches fused battery current to the rear glass heating grid and the Light-Emitting
Diode (LED) indicator of the rear window defogger switch, when the Body Control Module (BCM) rear window defogger timer and logic circuitry
grounds the relay coil. The rear window defogger relay is located in the right rear trunk area behind the carpeting.
The rear window defogger relay is a International Standards Organization (ISO) relay. Relays conforming to the ISO specifications have common
physical dimensions, current capacities, terminal patterns, and terminal functions.
The rear window defogger relay cannot be repaired or adjusted and, if faulty or damaged, it must be replaced.
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 the electromagnetic coil is energized, it draws the
movable contact away from the normally closed fixed contact, and holds it against the other (normally open) fixed contact.
When the electromagnetic coil is de-energized, spring pressure returns the movable contact to the normally closed position. The resistor or diode is
connected in parallel with the electromagnetic coil in the relay, and helps to dissipate voltage spikes that are produced when the coil is de-energized.