
²accessories being left on with the engine not run-
ning
²a faulty or improperly adjusted switch that allows
a lamp to stay on (see Ignition-Off Draw, in this
group).
INSPECTION
(1) Inspect condition of battery cable terminals,
battery posts, connections at engine block, starter so-
lenoid and relay. They should be clean and tight. Re-
pair as required.
(2) Inspect all fuses in the fuseblock module and
Power Distribution Center (PDC) for tightness in re-
ceptacles. They should be properly installed and
tight. Repair or replace as required.
(3) Inspect the electrolyte level in the battery. If
cell caps are removable, add water if required. If cell
caps are not removable, replace battery if electrolyte
level is low.
(4) Inspect generator mounting bolts for tightness.
Replace or tighten bolts, if required. Refer to Group
8B - Battery/Starter/Generator Service for torque
specifications.
(5) Inspect generator drive belt condition and ten-
sion. Tighten or replace belt as required. Refer to
Belt Tension Specifications in Group 7 - Cooling Sys-
tem.
(6) Inspect connections at generator field, battery
output, and ground terminals. Also check ground con-
nection at engine. They should all be clean and tight.
Repair as required.
OUTPUT WIRE RESISTANCE TEST
This test will show the amount of voltage drop
across the generator output wire, from the generator
battery terminal to the battery positive post.
PREPARATION
(1) Before starting test make sure vehicle has a
fully-charged battery. See Battery in this group for
more information.
(2) Turn ignition switch to OFF.
(3) Disconnect negative cable from battery.
(4) Disconnect generator output wire from genera-
tor battery output terminal.
(5) Connect a 0-150 ampere scale DC ammeter
(Fig. 2). Install in series between generator battery
output terminal and disconnected generator output
wire. Connect positive lead to generator battery out-
put terminal and negative lead to disconnected gen-
erator output wire.
(6) Connect positive lead of a test voltmeter (range
0-18 volts minimum) to disconnected generator out-
put wire. Connect negative lead of test voltmeter to
battery positive cable at positive post.
(7) Connect one end of a jumper wire to ground
and with other end probe green K20 field wire at
back of generator (Fig. 2). This will generate a DTC.CAUTION: Do not connect green/orange A142 field
wire to ground. Refer to Group 8W - Wiring Dia-
grams for more information.
(8) Connect an engine tachometer, then connect
battery negative cable to battery.
(9) Connect a variable carbon pile rheostat be-
tween battery terminals. Be sure carbon pile is in
OPEN or OFF position before connecting leads. See
Load Test in this group for instructions.
TEST
(1) Start engine. Immediately after starting, re-
duce engine speed to idle.
(2) Adjust engine speed and carbon pile to main-
tain 20 amperes flowing in circuit. Observe voltmeter
reading. Voltmeter reading should not exceed 0.5
volts.
RESULTS
If a higher voltage drop is indicated, inspect, clean
and tighten all connections. This includes any con-
nection between generator battery output terminal
and battery positive post. A voltage drop test may be
performed at each connection to locate the connection
with excessive resistance. If resistance tests satisfac-
torily, reduce engine speed, turn OFF carbon pile and
turn OFF ignition switch.
(1) Disconnect negative cable from battery.
(2) Remove test ammeter, voltmeter, carbon pile,
and tachometer.
(3) Remove jumper wire.
(4) Connect generator output wire to generator
battery output terminal. Tighten nut to 8.561.5 Nzm
(75615 in. lbs.).
(5) Connect negative cable to battery.
(6) Use DRB scan tool to erase DTC.
CURRENT OUTPUT TEST
The generator current output test determines
whether generator can deliver its rated current out-
put.
PREPARATION
(1) Before starting test make sure vehicle has a
fully-charged battery. See Battery in this group for
more information.
(2) Disconnect negative cable from battery.
(3) Disconnect generator output wire at the gener-
ator battery output terminal.
(4) Connect a 0-150 ampere scale DC ammeter
(Fig. 3). Install in series between generator battery
output terminal and disconnected generator output
wire. Connect positive lead to generator battery out-
put terminal and negative lead to disconnected gen-
erator output wire.
8A - 18 BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICSJ

DIAGNOSIS
WARNING: ON VEHICLES EQUIPPED WITH AN AIR-
BAG, REFER TO GROUP 8M - RESTRAINT SYS-
TEMS BEFORE ATTEMPTING STEERING WHEEL
COMPONENT DIAGNOSIS OR SERVICE. FAILURE
TO TAKE PROPER PRECAUTIONS COULD RESULT
IN ACCIDENTAL AIRBAG DEPLOYMENT AND POS-
SIBLE PERSONAL INJURY.
(1) Inspect fuses (F8 and F16 in PDC on YJ)(11 in
fuseblock module and F14 in PDC on XJ). Replace
fuses, as required.
(2) Remove the horn relay (in the PDC on YJ)(in
the relay center on XJ). See Horn Relay Connec-
tions-XJ (Fig. 1) or Horn Relay Connections-YJ (Fig.
2) and perform the following tests.
²The common feed terminal (30) is connected to
battery voltage and should be hot at all times. If bat-
tery voltage is not present at relay cavity 30, check
circuit to fuse (F16 on YJ)(11 on XJ). Repair as re-
quired.
²The normally closed terminal (87A) is connected to
terminal 30 in the de-energized position, but is not
used for this application.
²The normally open terminal (87) is connected to
the common feed terminal (30) in the energized posi-
tion. This terminal supplies battery voltage to the
horn. There should be continuity between relay cav-
ity 87 and the horn terminal at all times. If not, re-
pair wiring or connections as required.
²The coil battery terminal (86) is connected to the
electromagnet in the relay, and battery voltage
should be present at all times. If battery voltage is
not present at relay cavity 86, check circuit to fuse
(F16 on YJ)(11 on XJ). Repair as required.
²The coil ground terminal (85) is connected to the
electromagnet in the relay. It is grounded when the
horn switch is depressed. Check for continuity to
ground at relay cavity 85 with the horn switch de-
pressed. If no continuity is found with horn switch
depressed or, if continuity is found with horn switch
released, repair horn switch or wiring as required.
See Horn Switch Remove/Install in this group for ser-
vice procedures.
If all relay connections check OK, proceed to next
step.
(3) With the horn relay still removed, check the
horn relay by performing the following tests.
²A relay in the de-energized position should have
continuity between terminal 87A and terminal 30,
and no continuity between terminal 87 and terminal
30.
²Resistance value between terminals 85 and 86
(electromagnet) is 7565 ohms.²Connect a battery to terminals 85 and 86. There
should now be continuity between terminal 87 and
terminal 30.
If relay fails any of the above tests, replace faulty
relay. If relay checks OK, reinstall and proceed to
next step.
(4) Disconnect wiring at horn terminal. Depress
horn switch. There should be battery voltage at the
horn wiring connector. If not, repair wiring to relay.
If OK, proceed to next step.
(5) Measure the resistance between the horn
bracket and a good chassis ground. The meter should
read zero ohms. If not, clean and tighten ground con-
nection between horn mounting screw and bracket. If
OK, replace faulty horn(s).
Fig. 1 Horn Relay Connections-XJ
Fig. 2 Horn Relay Connections-YJ
8G - 2 HORNSJ

DIAGNOSIS
BUZZER MODULE
(1) Check fuses (15 and 17 - XJ, 3 and 9 - YJ) in
the fuseblock module. If fuses are OK, go to next
step. If not OK, replace fuses as required.
(2) Check for battery voltage at fuse (15 - XJ, 3 -
YJ) in fuseblock module. If OK, go to next step. If not
OK, repair feed circuit from power distribution center
as required.
(3) Turn ignition switch to ON position. Check for
battery voltage at fuse (17 - XJ, 9 - YJ) in the fuse-
block module. If OK, go to next step. If not OK, re-
pair feed from ignition switch as required.
(4) Turn ignition switch to OFF position. Replace
buzzer module with a known good unit and test op-
eration. If not OK, remove buzzer module and go to
next step.
(5) Check for battery voltage at cavity for buzzer
terminal 7 in buzzer module connector (Fig. 1). If
OK, go to next step. If not OK, repair circuit to fuse
(15 - XJ, 3 - YJ).
(6) Turn ignition switch to ON position. Check for
battery voltage at cavity for buzzer terminal 1 in
buzzer module connector. If OK, go to next step. If
not OK, repair circuit to fuse (17 - XJ, 9 - YJ) in fuse-
block module.
(7) Turn ignition switch to OFF position. Check for
continuity between cavity for buzzer terminal 3 and
a good ground. There should be continuity. If OK, go
to diagnosis for switch that is related to buzzer mal-
function. If not OK, repair circuit to ground as re-
quired.
DRIVER'S DOOR JAMB SWITCH
(1) Open driver's door and note whether interior
lamps light. They should light. If OK, see diagnosis
for Ignition Key-In Switch (XJ or YJ) or Headlamp
Switch (XJ only). If not OK, go to next step.
(2) Check for continuity between door jamb switch
body and a good ground. There should be continuity.
If OK, go to next step. If not OK, tighten or clean
switch attachment to hinge pillar as required to re-
store ground path.
(3) Remove switch from hinge pillar and check
wire connections for clean and tight engagement. If
OK, replace faulty switch. If not OK, clean and
tighten connections as required.
IGNITION KEY-IN SWITCH
XJ MODELS
(1) Remove steering column shrouds (refer to
Group 8D - Ignition Systems for procedure). Unplug
ignition key-in switch connector from ignition switch
(Fig. 3). Open driver's door. Check for continuity be-
tween cavity 4 (black/light blue wire) and a good
ground. There should be continuity. If OK, go to next
step. If not OK, repair circuit to driver's door jamb
switch as required.
(2) Insert ignition key in ignition lock cylinder.
Check for continuity between key-in switch cavities 3
and 4 (Fig. 4). There should be continuity until key is
removed. If OK, go to next step. If not OK, replace
ignition switch.
(3) Check for continuity between key-in switch har-
ness connector cavity 3 (light blue wire) and cavity
for terminal 6 of buzzer module in buzzer module
connector. There should be continuity. If not OK, re-
pair circuit from switch to buzzer module as re-
quired.
Fig. 1 Buzzer Module Connector
Fig. 2 Buzzer Module Terminals
8U - 2 CHIME/BUZZER WARNING SYSTEMSJ

(2) Connect the other lead of the voltmeter to the
selected test point. The vehicle ignition may need to
be turned ON to check voltage. Refer to the appropri-
ate test procedure.
TESTING FOR CONTINUITY
(1) Remove the fuse for the circuit being checked or,
disconnect the battery.
(2) Connect one lead of the ohmmeter to one side of
the circuit being tested (Fig. 9).
(3) Connect the other lead to the other end of the
circuit being tested. Low or no resistance means good
continuity.
TESTING FOR A SHORT TO GROUND
(1) Remove the fuse and disconnect all items in-
volved with the fuse.
(2) Connect a test light or a voltmeter across the
terminals of the fuse.
(3) Starting at the fuse block, wiggle the wiring
harness about six to eight inches apart and watch the
voltmeter/test lamp.
(4) If the voltmeter registers voltage or the test
lamp glows, there is a short to ground in that general
area of the wiring harness.
TESTING FOR A SHORT TO GROUND ON
FUSES POWERING SEVERAL LOADS
(1) Refer to the wiring diagrams and disconnect or
isolate all items on the fused circuit.
(2) Replace the blown fuse.
(3) Supply power to the fuse by turning ON the
ignition switch or re-connecting the battery.(4) Start connecting the items in the fuse circuit
one at a time. When the fuse blows the circuit with
the short to ground has been isolated.
TESTING FOR A VOLTAGE DROP
(1) Connect the positive lead of the voltmeter to the
side of the circuit closest to the battery (Fig. 10).
(2) Connect the other lead of the voltmeter to the
other side of the switch or component.
(3) Operate the item.
(4) The voltmeter will show the difference in volt-
age between the two points.
TROUBLESHOOTING WIRING PROBLEMS
When troubleshooting wiring problems there are six
steps which can aid in the procedure. The steps are
listed and explained below. Always check for non-
factory items added to the vehicle before doing any
diagnosis. If the vehicle is equipped with these items,
disconnect them to verify these add-on items are not
the cause of the problem.
(1) Verify the problem.
(2) Verify any related symptoms. Do this by per-
forming operational checks on components that are in
the same circuit. Refer to the wiring diagrams.
(3) Analyze the symptoms. Use the wiring dia-
grams to determine what the circuit is doing, where
the problem most likely is occurring and where the
diagnosis will continue.
(4) Isolate the problem area.
(5) Repair the problem.
(6) Verify proper operation. For this step, check for
proper operation of all items on the repaired circuit.
Refer to the wiring diagrams.
Fig. 8 Testing for Voltage
Fig. 9 Testing for Continuity
JWIRING DIAGRAMSÐGENERAL INFORMATION 8W - 5