Dodge Ram Truck 1500-2500-3500. Manual — part 338

DEFOG RELAY CONTROL CKT SHORTED TO BATT (CONTINUED)

3.

CHECK FOR A SHORTED A/C HEATER CONTROL

Turn the ignition off.

Remove the Heated Mirror Relay and the EBL relay if equipped from
the Integrated Power Module.

Disconnect the A/C Heater Control C1 harness connector.

Turn the ignition on.

Measure the voltage of the (C110) Defogger Relay Control circuit at
the A/C Heater Control C1 harness connector.

Is there any voltage present?

Yes

>> Go To 4

No

>> Replace the A/C Heater Control in accordance with the

Service Information.

Perform BODY VERIFICATION TEST - VER 1. (Refer to
BODY VERIFICATION TEST - VER 1).

4.

CHECK THE (C110) DEFOGGER RELAY CONTROL CIRCUIT FOR A SHORT TO BATTERY

Turn the ignition off.

Disconnect the Integrated Power Module C5 harness connector.

Turn the ignition on.

Measure the voltage of the (C110) Defogger Relay Control circuit at
the A/C Heater Control C1 harness connector.

Is there any voltage present?

Yes

>> Repair the (C110) Defogger Relay Control circuit for a

short to battery.

Perform BODY VERIFICATION TEST - VER 1. (Refer to
BODY VERIFICATION TEST - VER 1).

No

>> Replace the Integrated Power Module in accordance with

the Service Information.

Perform BODY VERIFICATION TEST - VER 1. (Refer to
BODY VERIFICATION TEST - VER 1).

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HEATED GLASS - ELECTRICAL DIAGNOSTICS

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SCHEMATICS AND DIAGRAMS

HEA

TED

GLASS

SYSTEM

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HEATED GLASS - ELECTRICAL DIAGNOSTICS

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HEATED GLASS - SERVICE INFORMATION

TABLE OF CONTENTS

page

page

HEATED GLASS - SERVICE INFORMATION

DESCRIPTION

. . . . . . . . . . . . . . . . . . . . . . . . . . 6

OPERATION

. . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

DIAGNOSIS AND TESTING

ELECTRIC BACKLIGHT (EBL) AND HEATED

MIRROR SYSTEM . . . . . . . . . . . . . . . . . . . . . . 7

SWITCH-REAR WINDOW DEFOGGER

DESCRIPTION

. . . . . . . . . . . . . . . . . . . . . . . . . . 9

OPERATION

. . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

RELAY-REAR WINDOW DEFOGGER

DESCRIPTION

. . . . . . . . . . . . . . . . . . . . . . . . . 10

OPERATION

. . . . . . . . . . . . . . . . . . . . . . . . . . . 10

REMOVAL

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

INSTALLATION

. . . . . . . . . . . . . . . . . . . . . . . . . 11

GRID-REAR WINDOW DEFOGGER

STANDARD PROCEDURE

GRID LINE AND TERMINAL REPAIR

. . . . . . . 12

HEATED GLASS - SERVICE INFORMATION

DESCRIPTION

CAUTION: Grid lines can be damaged or scraped off with sharp instruments. Care should be taken in clean-
ing glass or removing foreign materials, decals or stickers. Normal glass cleaning solvents or hot water
used with rags or toweling is recommended.

The rear window defogger system, also known as
electric backlight (EBL), consists of two vertical bus
bars (1) linked by a series of grid lines (2) fired onto
the inside surface of the rear window (3).

The EBL system is turned On or Off by a switch and a
timing circuit integral to the A/C-heater control located
at the center of the instrument panel.

Circuit protection is provided by two cartridge fuses
located in the integrated power module (IPM). One
fuse is for the control circuit and the other fuse is for
the heated grid circuit.

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HEATED GLASS - SERVICE INFORMATION

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OPERATION

The electric backlight (EBL) system is controlled by a
momentary switch (1) located in the A/C-heater control
(2) on the instrument panel. When the rear window
defogger switch is pressed to the On position, the
A/C-heater control energizes the rear window defog-
ger (EBL) relay and the heated mirror relay, which
then directs battery current to the rear defogger grid
lines and to the heated side view mirrors. The grid
lines heat the glass to help clear the rear window and
side mirror surfaces of fog or frost.

An amber indicator (3) in the rear window defogger
switch will illuminate to indicate when the EBL system
is turned on. The A/C-heater control contains the EBL
system control circuitry including the timer logic.

NOTE: The EBL system turns off automatically
after approximately ten minutes of operation.

The EBL system will be automatically turned off after a
programmed time interval of about ten minutes each
time the rear window defogger switch is pressed. The EBL system will automatically shut off if the ignition switch is
turned to the Off position, or it can be turned off manually by pressing the rear window defogger switch a second
time.

Repair of the rear window defogger grid lines, bus bars, terminals or pigtail wires can be accomplished using the
Mopar Rear Window Defogger Repair Kit (Part Number 04549275) or equivalent (Refer to 8 - ELECTRICAL/
HEATED GLASS/REAR WINDOW DEFOGGER GRID - STANDARD PROCEDURE - GRID LINE AND TERMINAL
REPAIR).

DIAGNOSIS AND TESTING

ELECTRIC BACKLIGHT (EBL) AND HEATED MIRROR SYSTEM

NOTE: Illumination of the defogger switch indicator lamp does not necessary mean that electrical current is
reaching the rear window glass and/or the outside rear view mirror heating grids.

NOTE: For circuit descriptions and diagrams of the rear window defogger (EBL) and heated mirror systems,
refer to 8W - WIRING DIAGRAM INFORMATION.

Operation of the electrical backlight (EBL) and heated mirror systems can be confirmed by the following:

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HEATED GLASS - SERVICE INFORMATION

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