electric backlight (EBL), consists of two vertical bus
bars linked by a series of grid lines fired onto the
inside surface of the rear window (Fig. 1).

The EBL system is turned On or Off by a switch in

the A/C-heater control located at the center of the
instrument panel and by a rear window defogger tim-
ing circuit integral to the integrated power module
(IPM).

Circuit protection is provided by a 40 amp fuse

located in the IPM.

OPERATION

The electric backlight (EBL) system is controlled

by a momentary switch located in the A/C-heater
control on the instrument panel (Fig. 2). When the

rear window defogger switch is pressed to the On
position, the integrated power module (IPM) ener-
gizes the rear window defogger (EBL) relay and bat-
tery current is then directed through the relay and to
the rear defogger grid lines and the heated side view
mirrors (when equipped). The grid lines heat the

Fig. 1 Rear Window Defogger - Typical

1 - REAR DEFOGGER GRID
2 - REAR WINDOW

HEATED SYSTEMS

8G - 1

glass to help clear the rear window and side mirror
surfaces of fog or frost.

An amber indicator in the rear window defogger

switch will illuminate to indicate when the EBL sys-
tem is turned on. The IPM contains the EBL system
control circuitry including the timer logic.

NOTE: The EBL system turns off automatically after
10 minutes of initial operation. Each following acti-
vation cycle of the EBL system will last five min-
utes.

The EBL system will be automatically turned off

after an initial programmed time interval of about
ten minutes. After the initial time interval has
expired, if the rear window defogger switch is turned
on again during the same ignition cycle, the EBL sys-
tem will automatically turn off after about five min-
utes. 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 win-
dow 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) SYSTEM

NOTE: Illumination of the defogger switch indicator
lamp means that there is electrical current available
at the output of the rear window defogger logic cir-
cuitry, but does not confirm that the electrical cur-
rent is reaching the rear glass heating grid lines.

NOTE: For circuit descriptions and diagrams of the
rear window defogger system, refer to 8W - WIRING
DIAGRAM INFORMATION.

Operation of the electrical backlight (EBL) system

can be confirmed by the following:

(1) Turn the ignition switch to the On position. Set

the defogger switch in the On position. The rear win-
dow defogger operation can be checked by feeling the
rear window glass. A distinct difference in tempera-
ture between the grid lines and the adjacent clear
glass can be detected within three to four minutes of
operation.

(2) If a temperature difference is not detected, use

a 12-volt DC voltmeter and contact the rear glass
heating grid terminal B with the negative lead, and
terminal A with the positive lead (Fig. 3). The volt-
meter should read battery voltage. If the voltmeter
does not read battery voltage, check the following:

• Confirm that the ignition switch is ON.

• Make sure that the rear glass heating grid feed

wire and ground wire are connected to the terminals.
Confirm that the ground wire has continuity to
ground.

• Check that fuse 5 (40 amp) in the integrated

power module (IPM) is OK. The fuse must be tight in
it’s receptacle and all electrical connections must be
secure.

(3) When the above steps have been completed and

the rear glass heating grid is still inoperative, one or
more of the following is faulty. It may be necessary to
connect a DRBIII

t scan tool to perform further diag-

nostics. Refer to Body Diagnostic Procedures.

• Rear window defogger switch in the A/C-heater

control.

• J1850 bus communication between the A/C-

heater control and the IPM.

• Rear window defogger (EBL) relay in the IPM.

• Rear window defogger (EBL) relay control circu-

ity in the IPM.

• Check for a loose wire connector or a wire

pushed out of a connector.

• Rear window grid lines (all grid lines would

have to be broken, or the power feed or ground wire
not connected, for the entire heating grid to be inop-
erative).

Fig. 2 Rear Window Defogger Switch

1 - A/C-HEATER CONTROL
2 - REAR WINDOW DEFOGGER (EBL) SWITCH

8G - 2

HEATED GLASS

HEATED GLASS (Continued)

Content .. 490 491 492 493 ..