Durango 2WD V8-5.7L Hybrid (2009)
Heated Glass Element Relay: Description and Operation
Rear Defogger Relay - Operation
OPERATION
The ISO-standard rear window defogger (EBL) relay is an electromechanical switch that uses a low current input controlled by the front control module
(FCM) to control the high current output to the rear window defogger grid lines. The movable, common feed relay contact is held against the fixed,
normally closed relay contact by spring pressure. When the electromagnetic relay coil is energized, it draws the movable common feed relay contact
away from the fixed, normally closed relay contact and, holds it against the fixed, normally open relay contact. This action allows high current to flow to
the rear window defogger grid lines.
When the relay coil is de-energized, spring pressure returns the movable relay contact back against the fixed, normally closed contact point. The resistor
or diode is connected in parallel with the relay coil, and helps to dissipate voltage spikes and electromagnetic interference that can be generated as the
electromagnetic field of the relay coil collapses.
The EBL relay terminals are connected to the vehicle electrical system through a receptacle in the junction block (JB). The inputs and outputs of the
EBL relay include:
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The common feed terminal (30) receives fused battery current at all times.
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The coil ground terminal (85) receives a ground through the EBL relay control circuit only when the front control module (FCM) electronically
pulls the circuit to ground.
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The coil battery terminal (86) receives fused battery current through an ignition switch output circuit only when the ignition switch is in RUN.
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The normally open terminal (87) provides battery current to the rear window defogger grid lines through the EBL relay output circuit only when
the EBL relay coil is energized.
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The normally closed terminal (87A) is not connected to any circuit in this application, but provides a battery current output only when the EBL
relay coil is de-energized.
The EBL relay cannot be adjusted or repaired and must be replaced if inoperative or damaged. See Wiring Information for diagnosis and testing of the
EBL relay and for complete rear window defogger (EBL) wiring diagrams.
