Dodge Nitro. Manual — part 539

RELAY-REAR WINDOW DEFOGGER

The rear window defogger (EBL) relay is an electromechanical switch that uses a low current input controlled
by the totally integrated power module (TIPM) to control the high current output to the rear window defogger
grid lines and to the heated outside mirrors, when equipped. 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 TIPM located
in the engine compartment. The inputs and outputs of the EBL relay include:

Terminal (30) receives battery current at all times.

Terminal (85) receives a ground through the EBL control circuit of the TIPM only when the module
electronically pulls the circuit to ground.

Terminal (86) receives battery current at all times.

Terminal (87) provides battery current to the rear window defogger grid and to the heated outside mirrors,
only when the EBL relay coil is energized.

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 repaired and must be replaced if inoperative or damaged. Refer to the appropriate
wiring information for diagnosis and testing of the ISO relay and for complete rear window defogger (EBL)
wiring diagrams.

REMOVAL

RELAY-REAR WINDOW DEFOGGER

2007 Dodge Nitro R/T

2007 ACCESSORIES AND EQUIPMENT Heated Glass - Service Information - Nitro

Fig. 6: Identifying Power Module (TIPM) & EBL Relay
Courtesy of CHRYSLER LLC

1. Disconnect and isolate the negative battery cable.

2. Open the cover on the totally integrated power module (TIPM) (1) located in the engine compartment.

3. Remove the EBL relay (2) from the TIPM.

INSTALLATION

RELAY-REAR WINDOW DEFOGGER

Fig. 7: Identifying Power Module (TIPM) & EBL Relay
Courtesy of CHRYSLER LLC

NOTE:

Refer to the fuse and relay map on the inside of the TIPM cover for EBL
relay location.

2007 Dodge Nitro R/T

2007 ACCESSORIES AND EQUIPMENT Heated Glass - Service Information - Nitro

1. Position the EBL relay (2) to the TIPM (1).

2. Align the EBL relay terminals with the terminal cavities in the TIPM receptacle and push down firmly on

the relay until the terminals are fully seated.

3. Close the TIPM cover.

4. Reconnect the negative battery cable.

SWITCH-REAR WINDOW DEFOGGER

DESCRIPTION

SWITCH-REAR WINDOW DEFOGGER

Fig. 8: Identifying Push-Button Switch & A/C-Heater Control
Courtesy of CHRYSLER LLC

The switch for the rear window defogger (EBL) system (1) is integral to the blower speed control located on the
A/C-heater control (2) in the instrument panel. When the rear window defogger switch is pressed to the On
position, a request signal is sent over the CAN-IHS bus to the totally integrated power module (TIPM) to
operate the EBL system and the amber indicator (3) illuminates.

When the EBL relay is energized, current is directed to the rear defogger grid lines and to the heated side view
mirrors, when equipped. The grid lines heat the glass to help clear the rear window and side mirror surfaces of
fog or frost.

OPERATION

SWITCH-REAR WINDOW DEFOGGER

The amber indicator located in the blower speed control of the A/C-heater control will illuminate when the EBL

NOTE:

Refer to the fuse and relay map on the inside of the totally integrated power
module (TIPM) cover for EBL relay location.

2007 Dodge Nitro R/T

2007 ACCESSORIES AND EQUIPMENT Heated Glass - Service Information - Nitro

system is operating. When the rear window defogger switch is pressed to the On position with the ignition
switch in RUN, the switch sends a request signal to the totally integrated power module (TIPM), which then
provides a ground path to energize the coil in the EBL relay. When energized, the EBL relay provides fused
battery current to the rear window defogger grid lines and to the heated side view mirrors, when equipped.

The EBL system will be automatically turned off after an initial programmed time interval of about 10 minutes
as long as the ignition switch is in RUN. After the initial time interval has expired, if the rear window defogger
switch is pressed to the On position again during the same ignition cycle, the EBL system will automatically
turn off after about 5 minutes. The EBL system will automatically shut off if the ignition switch is turned to any
position other than RUN, or it can be turned off manually by pressing the rear window defogger switch a second
time.

The rear window defogger switch is diagnosed using a scan tool (refer to HEATING & AIR
CONDITIONING - ELECTRICAL DIAGNOSTICS for more information).

The rear window defogger switch and indicator cannot be adjusted or repaired and the A/C-heater control must
be replaced if inoperative or damaged. Refer to REMOVAL .

NOTE:

The EBL system turns off automatically after 10 minutes of initial operation.
Each following activation cycle of the EBL system will last 5 minutes.

2007 Dodge Nitro R/T

2007 ACCESSORIES AND EQUIPMENT Heated Glass - Service Information - Nitro