Horn Systems - Jeep 1997 Grand Cherokee Service Manual

ZG
GENERAL INFORMATION
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . 1
DESCRIPTION AND OPERATION
BODY CONTROL MODULE . . . . . . . . . . . . . . . . 2
HORN RELAY . . . . . . . . . . . . . . . . . . . . . . . . . . 1
HORN SWITCH . . . . . . . . . . . . . . . . . . . . . . . . . 1
HORN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
DIAGNOSIS AND TESTING
HORN RELAY . . . . . . . . . . . . . . . . . . . . . . . . . . 2
GENERAL INFORMATION
INTRODUCTION
Following are general descriptions of the major
components in the factory-installed horn systems.
Refer to 8W-41 - Horns/Cigar Lighter in Group 8W -
Wiring Diagrams for complete circuit descriptions
and diagrams.
NOTE: This group covers both Left-Hand Drive
(LHD) and Right-Hand Drive (RHD) versions of this
model. Whenever required and feasible, the RHD
versions of affected vehicle components have been
constructed as mirror-image of the LHD versions.
While most of the illustrations used in this group
represent only the LHD version, the diagnostic and
service procedures outlined can generally be
applied to either version. Exceptions to this rule
have been clearly identified as LHD or RHD, if a
special illustration or procedure is required.
DESCRIPTION AND OPERATION
HORN RELAY
The horn relay is a International Standards Orga-
nization (ISO) micro-relay. The terminal designations
and functions are the same as a conventional ISO
relay. However, the micro-relay terminal orientation
(or footprint) is different, current capacity is lower,
and the relay case dimensions are smaller than those
of the conventional ISO relay.
The horn relay is a electromechanical device that
switches battery current to the horn when the horn
switch grounds the relay coil. See the Diagnosis and
Testing section of this group for more information on
the operation of the horn relay.

HORN SYSTEMS

CONTENTS
page
HORN SWITCH . . . . . . . . . . . . . . . . . . . . . . . . . 3
HORN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
REMOVAL AND INSTALLATION
HORN RELAY
HORN SWITCH . . . . . . . . . . . . . . . . . . . . . . . . . 4
HORN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
The horn relay is located in the Power Distribution
Center (PDC), in the engine compartment. Refer to
the PDC label for relay identification and location.
If a problem is encountered with a continuously
sounding horn, it can usually be quickly resolved by
removing the horn relay from the PDC until further
diagnosis is completed.
The horn relay cannot be repaired and, if faulty or
damaged, it must be replaced.
HORN SWITCH
A center-blow, resistive membrane type horn
switch is installed on the back side of the driver side
airbag module trim cover in the center of the steer-
ing wheel. When the center area of the airbag trim
cover is depressed, the horn switch completes a cir-
cuit to ground for the coil side of the horn relay. The
steering wheel and steering column must be properly
grounded for the horn switch to function.
The horn switch is only serviced as a part of the
airbag module trim cover. If the horn switch should
fail, or if the airbag is deployed, the airbag module
trim cover and horn switch unit must be replaced.
HORN
The
phragm-type horns are secured next to each other on
a bracket beneath the right radiator closure exten-
sion panel and forward of the right front inner
wheelhouse. The two horns are connected in parallel
and are grounded through their wire harness connec-
tor and circuit to an eyelet bolted to the right inner
fender shield near the Power Distribution Center
(PDC), and receive battery feed through the closed
contacts of the horn relay.
The horns cannot be repaired or adjusted and, if
faulty or damaged, they must be replaced.
HORN SYSTEMS
. . . . . . . . . . . . . . . . . . . . . . . . . . 3
standard, dual-note,
8G - 1
page
electromagnetic dia-