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Jeep Liberty KJ. Manual - part 115

TRAILER TOW CONNECTOR

REMOVAL

1. Disconnect and isolate the battery negative cable.

2. Remove the four screws (3) that secure the trailer

tow connector (2) to the bracket (4) on the trailer
hitch receiver (1).

3. Pull the trailer tow connector rearward from the

hitch receiver bracket far enough to access and
disconnect the rear body wire harness connector
(5).

4. Remove the trailer tow connector from the trailer

hitch receiver.

INSTALLATION

1. Position the trailer tow connector (2) to the trailer

hitch receiver (1).

2. Reconnect the rear body wire harness connector

(5) to the trailer tow connector.

3. Position the trailer tow connector into the bracket

(4) on the trailer hitch receiver.

4. Install and tighten the four screws (3) that secure

the trailer tow connector to the hitch receiver
bracket. Tighten the screws to 4 N·m (35 in. lbs.).

5. Reconnect the battery negative cable.

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LAMPS/LIGHTING - EXTERIOR

TRAILER TOW RELAY

DESCRIPTION

Vehicles equipped with an optional factory-installed
trailer towing package have four trailer tow relays. The
trailer tow relays are conventional International Stan-
dards Organization (ISO) micro relays. Relays con-
forming to the ISO specifications have common
physical dimensions, current capacities, terminal pat-
terns, and terminal functions. Each relay is contained
within a small, rectangular, molded plastic housing and
is connected to all of the required inputs and outputs
through five integral male spade-type terminals that
extend from the relay base plate.

The trailer tow relays include one each for brake lamps (5), right turn lamps (4), left turn lamps (3) and a fused
ignition switch output (run) circuit (6) which are provided for the trailer through the rear body wiring (2) and con-
nectors. The relays are located in a connector bank (1) above the right rear wheelhouse and behind the quarter trim
panel. The connector bank and relays are wrapped within a foam rubber isolator envelope for sound deadening and
anti-rattle protection.

Refer to Trailer Tow in the wiring information for specific relay cavity assignment information. A trailer tow relay
cannot be adjusted or repaired and, if ineffective or damaged, the unit must be replaced.

OPERATION

The trailer tow relays are electromechanical switches that each use a low current input from the circuit that they
isolate to control a high current output to the trailer brake and turn signal lamps, and a trailer accessory circuit.
Within each relay are an electromagnetic coil, a movable contact and two fixed contact points. A resistor is con-
nected in parallel with the coil, and helps to dissipate voltage spikes and electromagnetic interference that can be
generated as the field of the relay coil collapses.

The movable common supply contact point is held against the fixed normally closed contact point by spring pres-
sure. When the relay coil is energized, an electromagnetic field is produced by the coil windings. This field draws
the movable contact away from the normally closed contact, and holds it against the normally open contact. When
the relay coil is de-energized, spring pressure returns the movable contact back against the normally closed contact.

The inputs and outputs of the trailer tow relays include:

•

Common Supply Terminal (30) - The common feed terminal is connected to the circuit connected to the nor-
mally open terminal (87) when the relay is energized, or to the circuit connected to the normally closed ter-
minal (87A) when the relay is de-energized.

•

Coil Ground Terminal (85) - The coil ground terminal is connected to a ground circuit at all times.

•

Coil Battery Terminal (86) - The coil battery terminal is connected to the circuit that controls the relay output.
When battery voltage is applied to this terminal, the relay is energized.

•

Normally Open Terminal (87) - The normally open terminal is connected to the circuit connected to the com-
mon supply terminal (30) whenever the relay is energized.

•

Normally Closed Terminal (87A) - The normally closed terminal is connected to the circuit connected to the
common supply terminal (30) whenever the relay is de-energized.

The trailer tow relays can be diagnosed using conventional diagnostic tools and methods. Refer to the appropriate
wiring information.

LAMPS/LIGHTING - EXTERIOR

8L - 119

REMOVAL

WARNING: To avoid personal injury or death, on vehicles equipped with airbags, disable the supplemental
restraint system before attempting any steering wheel, steering column, airbag, occupant classification sys-
tem, seat belt tensioner, impact sensor, or instrument panel component diagnosis or service. Disconnect
and isolate the battery negative (ground) cable, then wait two minutes for the system capacitor to discharge
before performing further diagnosis or service. This is the only sure way to disable the supplemental
restraint system. Failure to take the proper precautions could result in accidental airbag deployment.

CAUTION: Use proper precautions to protect your skin and the rear body wire harness from cuts or scrapes
caused by contact with the sharp edges of the quarter inner panel sheet metal while servicing the trailer
tow relay connector bank.

CAUTION: Be certain any removed trailer tow relay is replaced with the same relay size and type that was
removed.

NOTE: The trailer tow relay bank contains four relays. The service procedures for each relay are the same.

1. Disconnect and isolate the battery negative cable.

2. Remove the trim from the right side quarter inner

panel. (Refer to 23 - BODY/INTERIOR/QUARTER
TRIM PANEL - REMOVAL).

3. Reach through the access hole in the quarter inner

panel behind the right rear wheelhouse to locate
and retrieve the trailer tow relay connector bank at
the end of a take out of the rear body wire harness
(2), which is wrapped within a foam rubber enve-
lope (1) and placed on the top of the right rear
wheelhouse between the quarter inner and outer
panels.

4. Pull the trailer tow relay connector bank envelope

into the cargo area far enough to access the relays
for service.

5. Carefully remove the trailer tow relay connector

bank (1) from the foam wrap.

6. Remove the appropriate relay (3, 4, 5 or 6) by

grasping it firmly and pulling it straight out from the
connector bank.

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LAMPS/LIGHTING - EXTERIOR

INSTALLATION

CAUTION: Be certain any removed trailer tow relay is replaced with the same relay size and type that was
removed.

NOTE: The trailer tow relay bank contains four relays. The service procedures for each relay are the same.

1. Position the trailer tow relay (3, 4, 5 or 6) to the

appropriate connector in the connector bank (1).

2. Align the relay terminals with the receptacles in the

connector.

3. Push firmly and evenly on the top of the relay until

the terminals are fully seated in the connector.

4. Carefully restore the foam wrap (1) around the

trailer tow relay connector bank on the rear body
wire harness take out (2).

5. Reach through the access hole in the quarter inner

panel behind the right rear wheelhouse to place the
relay connector bank on the top of the right rear
wheelhouse between the quarter inner and outer
panels.

6. Reinstall the trim onto the right side quarter inner

panel. (Refer to 23 - BODY/INTERIOR/QUARTER
TRIM PANEL - INSTALLATION).

7. Reconnect the battery negative cable.

LAMPS/LIGHTING - EXTERIOR

8L - 121

Content .. 113 114 115 116 ..