belt DODGE NEON 1999 Service User Guide

COOLING SYSTEM DIAGNOSIS CONT.
CONDITION POSSIBLE CAUSES CORRECTION
INADEQUATE AIR CONDITIONER
PERFORMANCE (COOLING
SYSTEM SUSPECTED)1. Radiator and/or air conditioning
condenser is restricted, obstructed
or dirty.1. Remove restriction and/or clean
as necessary.
2. Electric radiator fan not operating
when a/c is on.2. Refer to appropriate Powertrain
Diagnostic Procedures manual for
operation of the DRB scan tool.
repair as necessary.
3. Engine is overheating ( heat may
be transferred from radiator to A/C
condenser. High underhood
temperature due to engine
overheating may also transfer heat
to A/C components).3. Correct overheating condition.
Refer to Group 7, Cooling.
INADEQUATE HEATER
PERFORMANCE.1. Has a diagnostic trouble code
(DTC) been set?1. Refer to On-Board Diagnostic in
Group 25, and replace thermostat if
necessary.
2. Coolant level low. 2. Refer to testing cooling system
for leaks in this section. Repair as
necessary.
3. Obstructions in heater hose
fittings at engine.3. Remove heater hoses at both
ends and check for obstructions.
Repair as necessary.
4. Heater hose kinked. 4. Locate kinked area and repair as
necessary.
5. Water pump is not pumping
coolant to heater core. When the
engine is fully warmed up, both
heater hoses should be hot to the
touch. The accessory drive belt
may be slipping causing poor water
pump operation.5. Refer to water pump in this
group. Repair as necessary. If
slipping belt is detected, refer to
accessory drive belts in this group.
Repair as necessary.
HEAT ODOR 6. Various heat shields are used at
certain drive line components. One
or more of these shields may be
missing.6. Locate missing shields and
replace or repair as necessary.
PLCOOLING 7 - 11
DIAGNOSIS AND TESTING (Continued)

ENGINE THERMOSTAT TESTING
The thermostat is operated by a wax filled con-
tainer (pellet) which is sealed. When heated coolant
reaches a predetermined temperature the wax pellet
expands enough to overcome the closing spring and
water pump pressure, which forces the valve to open.
Coolant leakage into the pellet will cause a thermo-
stat to fail open. Do not attempt to free up a thermo-
stat with a screwdriver.The thermostat that opens too soon type failure
mode is included in the on-board diagnosis. The
check engine light will not be lit by an open too soon
condition. If it has failed open, a diagnostic trouble
code (DTC) will be set. Do not change a thermostat
for lack of heater performance or temperature gauge
position, unless a DTC is present. See Diagnosis for
other probable causes. Thermostat failing shut is the
normal long term mode of failure, and normally, only
on high mileage vehicles. The temperature gauge will
indicate this. Refer to Diagnosis in this section.
ACCESSORY DRIVE BELT DIAGNOSIS
CONDITION POSSIBLE CAUSE CORRECTION
INSUFFICIENT ACCESSORY
OUTPUT DUE TO BELT SLIPPAGE1. Belt too loose. 1. Adjust belt tension.
2. Belt excessively glazed or worn. 2. Replace and tighten as specified.
BELT SQUEAL WHEN
ACCELERATING ENGINE1. Belts too loose. 1. Adjust belt tension.
2. Belts glazed. 2. Replace belts.
BELT CHIRP AT IDLE 1. Belts too loose. 1. Adjust belt tension.
2. Foreign material imbedded in
belt.2. Replace belt.
3. Non-uniform belt. 3. Replace belt.
4. Misaligned pulley(s). 4. Align accessories.
5. Non-uniform groove or eccentric
pulley.5. Replace pulley(s).
BELT ROLLED OVER IN GROOVE
OR BELT JUMPS OFF1. Broken cord in belt. 1. Replace belt.
2. Belt too loose, or too tight. 2. Adjust belt tension.
3. Misaligned pulleys. 3. Align accessories.
4. Non-uniform grooves or eccentric
pulley.4. Replace pulley(s).
PLCOOLING 7 - 13
DIAGNOSIS AND TESTING (Continued)

COOLING SYSTEMÐREFILLING
First clean system to remove old glycol, see Cooling
System Cleaning.
Fill system using antifreeze described in Coolant
section. Fill 50 percent of capacity with 100 percent
glycol. Then complete filling system with water.
Continue filling system until full, this provides bet-
ter heater performance.Be careful not to spill
coolant on drive belts or the generator.
Fill coolant reserve system to at least the FULL
mark with 50/50 solution. It may be necessary to add
coolant to the reserve tank after three or four warm-
up/cool down cycles to maintain coolant level between
the FULL and ADD marks; if any trapped air was
removed from the system.
REMOVAL AND INSTALLATION
WATER PUMP
REMOVAL
(1) Raise vehicle on a hoist. Remove right inner
splash shield.
(2) Remove accessory drive belts and power steer-
ing pump. Refer to Accessory Drive Belt service in
this section.
(3) Drain cooling system. Refer to Cooling System
Draining in this section.
(4) Support engine from the bottom and remove
right engine mount.
(5) Remove power steering pump bracket bolts and
set pump and bracket assembly aside. Power steering
lines do not need to be disconnected.
(6) Remove right engine mount bracket.
(7) Remove timing belt and timing belt tensioner.
Refer to Group 9, Engine for procedure.
(8) Remove camshaft sprockets and inner timing
belt cover. Refer to Group 9, Engine for procedure.(9) Remove water pump attaching screws to engine
(Fig. 14).
INSTALLATION
(1) Install new O-ring gasket in water pump body
O-ring groove (Fig. 15). Use small dabs of Mopart
Silicone Rubber Adhesive Sealant around the water
pump body to secure O-ring in place during installa-
tion.
CAUTION: Make sure O-ring gasket is properly
seated in water pump groove before tightening
screws. An improperly located O-ring may cause
damage to the O-ring and cause a coolant leak.
(2) Assemble pump body to block and tighten
screws to 12 N´m (105 in. lbs.). Pressurize cooling
system to 15 psi with pressure tester and check
water pump shaft seal and O-ring for leaks.
(3) Rotate pump by hand to check for freedom of
movement.
(4) Install inner timing belt cover.
(5) Install timing belt. Refer to Group 9, Engine
for procedures.
(6) Install right engine mount bracket and engine
mount. Refer to Group 9, Engine for procedure.
(7) Fill cooling system. SeeCooling System
Refilling.
(8) Install power steering pump and accessory
drive belts, Refer to Accessory Drive Belts, in this
section.Fig. 13 Draining Cooling System
Fig. 14 Water Pump
Fig. 15 Water Pump Body
PLCOOLING 7 - 17
SERVICE PROCEDURES (Continued)

must be replaced withonlythe recommended part
for adequate strength, performance and safety.
(1) To remove fan from motor shaft, bench support
the motor and motor shaft, while removing the fan
retaining clip, so that the shaft and motor will not be
damaged by excessive force.Surface burr removal
may be required to remove fan from motor
shaft (Fig. 25).Do not permit the fan blades to
touch the bench.
(2) To install fan on motor shaft, slide the fan over
shaft. Support motor and shaft as above while
installing fan retaining clip.
INSTALLATION FAN MODULE
(1) Install module to radiator. Torque shroud to
radiator fasteners to 7.5 N´m (65 in. lbs.).
(2) Connect fan motor lead.For wiring diagrams
of fan motor systems Refer to 8W Wiring Dia-
grams.
ELECTRIC FAN MOTORÐSERVICE
WARNING: Do not disassemble the fan motor from
the support bracket.
Electric fan motor is serviced as an assembly with
the fan module.
FAN SHROUD
Some fan shrouds are equipped with flapped doors
to prevent the shroud from restricting air flow at
high speeds.
All vehicles have fan shrouds to improve fan air
flow efficiency.
The shroud supports the electric fan motor and
fan. For removal and installation procedures, refer to
radiator removal in this Section.
ENGINE BLOCK HEATER
REMOVAL
(1) Drain coolant from radiator and cylinder block.
Refer to Cooling System Drain, Clean, Flush and
Refill of this section for procedure.
(2) Detach power cord plug from heater.
(3) Loosen screw in center of heater. Remove
heater assembly.
INSTALLATION
(1) Thoroughly clean core hole and heater seat.
(2) Insert heater assembly with element loop posi-
tionedupward.
(3) With heater seated, tighten center screw
securely to assure a positive seal.
(4) Fill cooling system with coolant to the proper
level, vent air, and inspect for leaks. Pressurize sys-
tem with Radiator Pressure Tool before looking for
leaks.
ACCESSORY DRIVE BELTS
AIR CONDITIONING COMPRESSOR AND
POWER STEERING PUMP
(1) Loosen the power steering pump locking bolts
A and B and pivot bolt C (Fig. 26) to remove and
install belt and/or adjust belt tension.
(2) Using a 1/2º breaker bar, adjust belt tension by
applying torque to the square D hole on the power
steering pivot bracket. Adjust tension to specification
given in Belt Tension Chart.
(3) Tighten in order, first tighten locking bolt A to
27 N´m (20 ft. lbs.) then, bolt B to 27 N´m (20 ft. lbs.)
Then pivot bolt C to 54 N´m (40 ft. lbs.).
GENERATOR BELT
(1) Loosen pivot bolt E then locking nut F and
adjusting bolt G (Fig. 27) to remove and install belt
and/or adjust belt tension.
(2) Tighten adjusting bolt G, adjust belt tension to
specification shown in Belt Tension Chart.
(3) Tighten pivot bolt E to 54 N´m (40 ft. lbs.).
Locking nut F to 54 N´m (40 ft. lbs.).
CLEANING AND INSPECTION
WATER PUMP
Replace water pump body assembly if it has any of
these defects:
(1) Cracks or damage on the body.
(2) Coolant leaks from the shaft seal, evident by
coolant traces on the pump body.
(3) Loose or rough turning bearing.
(4) Impeller rubs either the pump body or the
engine block.
Fig. 25 Servicing Radiator Fan
PLCOOLING 7 - 21
REMOVAL AND INSTALLATION (Continued)

(5) Impeller loose or damaged.
(6) Sprocket or sprocket flange loose or damaged.
ACCESSORY DRIVE BELT INSPECTION
Belt replacement under any or all of the following
conditions is required, excessive wear, frayed cords or
severe glazing.
Poly-V-Belt system may develop minor cracks
across the ribbed side. These minor cracks are con-
sidered normal and acceptable. Cracks parallel are
not (Fig. 28).
NOTE: Do not use any type of belt dressing or
restorer on Poly-V-Belts.
COOLING SYSTEM CAP
Hold the cap in your hand,right side up(Fig. 29).
The vent valve at the bottom of the cap should open
with a slight pull. If the rubber gasket has swollen,
preventing the valve from opening, replace the cap.
If any light can be seen between vent valve and
the rubber gasket, replace the cap.Use only a
replacement cap that has a spring to hold the
vent shut.
A replacement cap must be of the type designed for
coolant reserve systems. This design ensures system
pressurization.
CLEANING COOLING SYSTEM
Drain cooling system (see:Draining Cooling Sys-
tem) and refill with clean water (see:Refilling
Fig. 26 Power Steering Pump Adjustment
BELT TENSION CHART
ACCESSORY
DRIVE BELTGAUGE TORQUE
Power Steering
Pump and A/C
CompressorNew 135 lb. 121 N´m (90 ft.
lbs.)
Used 100 lb. 81 N´m 60 ft.
lbs.)
Generator New 135 lb. Gauge
adjustment
method only Used 100 lb.
Fig. 27 Generator Adjustment
Fig. 28 Drive Belt Wear Pattern
7 - 22 COOLINGPL
CLEANING AND INSPECTION (Continued)

Cooling System). Run engine with radiator cap
installed until upper radiator hose is hot. Stop
engine and drain water from system. If water is
dirty, fill, run and drain system again until water
runs clear.
RADIATOR FLUSHING
Drain cooling system and remove radiator hoses
from engine. Install suitable flushing gun in radiator
lower hose. Fill radiator with clean water and turn
on air in short blasts.
CAUTION: Internal radiator pressure must not
exceed 138 kPa (20 psi) as damage to radiator may
result. Continue this procedure until water runs
clear.
ENGINE FLUSHING
Drain radiator (see:Cooling System Draining)
and remove hoses from radiator. Remove engine ther-
mostat and reinstall thermostat housing. A gasket
may be needed to seal the housing to cylinder head
because the seal is part of thermostat. Install suit-
able flushing gun to thermostat housing hose. Turn
on water, and when engine is filled, turn on air, but
no higher than 138 kPa (20 psi) in short blasts. Allowengine to fill between blasts of air. Continue this pro-
cedure until water runs clean. Install thermostat and
fill cooling system. Refer to (Cooling System Refill-
ing) for procedure.
REVERSE FLUSHING
Reverse flushing of the cooling system is the forc-
ing of water through the cooling system, using air
pressure in a direction opposite to that of the normal
flow of water. This is only necessary with dirty sys-
tems and evidence of partial plugging.
CHEMICAL CLEANING
One type of corrosion encountered with aluminum
cylinder heads is aluminum hydroxide deposits. Cor-
rosion products are carried to the radiator and depos-
ited when cooled off. They appear as dark grey when
wet and white when dry. This corrosion can be
removed with a two part cleaner (oxalic acid and
neutralizer) available in auto parts outlets. Follow
manufacturers directions for use.
ADJUSTMENTS
PROPER BELT TENSION
Satisfactory performance of the belt driven accesso-
ries depends on belt condition and proper belt ten-
sion. Refer to Accessory Drive Belt Inspection in this
section. There are two belt tensioning methods given
in order of preference:
²Belt tension gauge method.
²Torque equivalent method.
The belt tension gauge method usually requires the
vehicle to be raised on a hoist and the splash shield
removed.
TORQUE EQUIVALENT METHOD
Adjustable accessory brackets provided with a 13
mm (1/2 in.) square hole for a torque wrench can use
an equivalent torque value for belt adjustment.
Equivalent torque values for adjusting these acces-
sory drive belts are specified in the Belt Tension
Chart.
Fig. 29 Cooling System Pressure Cap
BELT TENSION CHART
ACCESSORY
DRIVE BELTGAUGE TORQUE
Power Steering
Pump and A/C
CompressorNew 135 lb. 121 N´m (90 ft.
lbs.)
Used 100 lb. 81 N´m 60 ft.
lbs.)
Generator New 135 lb. Gauge
adjustment
method only Used 100 lb.
PLCOOLING 7 - 23
CLEANING AND INSPECTION (Continued)

BELT TENSION GAUGE METHOD
NOTE: Use belt tensioning Special Tool Kit C-4162
for:
²For conventional belts and Poly-V-belts.
Adjust the belt tension for aNeworUsedbelt as
prescribed in the Belt Tension Chart.
SPECIFICATIONS
COOLING SYSTEM CAPACITYTORQUE
DESCRIPTION....................TORQUE
A/C Condenser to Radiator
Screws.....................7.2 N´m (65 in. lbs.)
Fan Module to Radiator
Screws.....................7.2 N´m (65 in. lbs.)
Fan Motor to Shroud (A/C equipped)
Screws.....................3.8 N´m (34 in. lbs.)
Fan Motor to Shroud (Non A/C equipped)
Screws.....................2.3 N´m (20 in. lbs.)
Radiator (Cooling Module) to Body
Screws.....................10N´m(90in.lbs.)
Thermostat Housing/Water Outlet Connector
Screws....................12N´m(105 in. lbs.)
Upper Radiator Crossmember
Bolts......................28N´m(250 in. lbs.)
Water Pump to Engine Block
Bolts......................12N´m(105 in. lbs.)
Water Pump Inlet Tube to Engine Block
Bolts......................12N´m(105 in. lbs.)
SPECIAL TOOLS
COOLING
BELT TENSION CHART
ACCESSORY DRIVE
BELTGAUGE
Power Steering Pump
and A/C CompressorNew 135 lb.
Used 100 lb.
Generator New 135 lb.
Used 100 lb.
COOLING SYSTEM CAPACITY CHART
7.00 LITERS 7.40 QTS.
CAPACITY, Includes Heater and Coolant Reserve
System
Accessory Drive Belt Tension Gauge C-4162
7 - 24 COOLINGPL
ADJUSTMENTS (Continued)

NOTE: BLACK OR DARK=0to75%state-of-charge
The battery is INADEQUATELY charged and must
be charged until green dot is visible, (12.4 volts or
greater) before the battery is tested or returned to
use. Refer to Causes of Battery Discharging in this
Group for more information.
NOTE: CLEAR COLOR = Replace Battery
WARNING: DO NOT CHARGE, ASSIST BOOST,
LOAD TEST, OR ADD WATER TO THE BATTERY
WHEN CLEAR COLOR DOT IS VISIBLE. PERSONAL
INJURY MAY OCCUR.
A clear color dot shows electrolyte level in battery
is below the test indicator (Fig. 1). Water cannot be
added to a maintenance free battery. The battery
must be replaced. A low electrolyte level may be
caused by an over charging condition. Refer to Gen-
erator Test Procedures on Vehicle.
CAUSES OF BATTERY DISCHARGING
It is normal to have a small 5 to 25 milliamperes
continuous electrical draw from the battery. This
draw will take place with the ignition in the OFF
position, and the courtesy, dome, storage compart-
ments, and engine compartment lights OFF. The con-
tinuous draw is due to various electronic features or
accessories that require electrical current with the
ignition OFF to function properly. When a vehicle is
not used over an extended period of approximately 20
days the IOD fuse should be pulled. The fuse is
located in the power distribution center. removal of
this fuse will reduce the level of battery discharge.
Refer to the Battery Diagnosis and Testing Table for
proper diagnosis.
ABNORMAL BATTERY DISCHARGING
²Corroded battery posts, cables or terminals.
²Loose or worn generator drive belt.
²Electrical loads that exceed the output of the
charging system due to equipment or accessories
installed after delivery.
²Slow driving speeds in heavy traffic conditions
or prolonged idling with high-amperage electrical
systems in use.
²Defective electrical circuit or component causing
excess Ignition Off Draw (IOD). Refer to Battery
Ignition Off Draw (IOD).
²Defective charging system.
²Defective battery.
BATTERY IGNITION OFF DRAW (IOD)
High current draw on the battery with the ignition
OFF will discharge a battery. After a dead battery is
recharged, the vehicle ignition off draw (IOD) shouldbe checked. To determine if a high current draw con-
dition exists first check the vehicle with a test lamp.
(1) Verify that all electrical accessories are OFF.
²Remove key from ignition switch
²Turn off all lights
²Trunk lid is closed
²Engine compartment hood lamp is disconnected
or lamp removed
²Glove box door is closed
²Sun visor vanity lights are OFF
²All doors are closed
²Allow the ignition key lamp system to time out
in approximately 30 seconds, if equipped.
(2) Disconnect battery negative cable (Fig. 4).
(3) Connect a 12 Volt test lamp, with a cold resis-
tance of 5-7 ohms, between the battery negative cable
clamp and the negative post (Fig. 5). If test lamp
goes out system is OK. If test lamp lights and stays
ON, go to Test Lamp Stays ON procedure.
TEST LAMP STAYS ON
There is either a short circuit or a fault in an elec-
tronic module. Two fuses in the Power Distribution
Center (PDC) feed the modules with ignition off
draw.
²Interior lamps fuse (10 Amp) (IOD) PDC.
²Fuel pump fuse (20 Amp) in PDC
(1) Remove interior lamp and fuel pump fuses. By
removing these fuses all ignition off draw from the
vehicle electronics will be disconnected. The test
lamp should go out. If test lamp goes out go to Step
2. If test lamp does not go out there is a current
draw or short circuit. Refer to Group 8W, Wiring Dia-
grams.
(2) Install the fuel pump fuse. If test lamp lights,
there is a current draw or short circuit in the A14
wiring circuit feed.
(a) Disconnect Powertrain Control Module.
(b) If test lamp goes out, replace Powertrain
Control Module.
(c) If test lamp does not go out, there is a cur-
rent draw or short circuit in the A14 circuit feed.
Refer to Group 8W, Wiring Diagrams.
(3) Install the interior lamp fuse. If test lamp
lights, there is a current draw or short circuit in the
M01 circuit. Refer to Group 8W, Wiring Diagrams. If
test lamp stays out, go to Step 4
(4) Use a multi-meter that has at least a range of
200 milliamperes. Install meter between the battery
negative cable and battery negative post (Fig. 6).
Carefully remove the test lamp without disconnecting
the meter. After all modules time-out the total vehi-
cle IOD should be less than 10 milliamperes. If igni-
tion off draw is more than 10 milliamperes go to Step
5.
(5) Remove both fuses from the Power Distribution
Center:
PLBATTERY 8A - 3
DIAGNOSIS AND TESTING (Continued)

CHARGING SYSTEM
CONTENTS
page page
GENERAL INFORMATION
OVERVIEW............................. 1
DESCRIPTION AND OPERATION
BATTERY TEMPERATURE SENSOR.......... 2
CHARGING SYSTEM OPERATION........... 1
ELECTRONIC VOLTAGE REGULATOR......... 2
GENERATOR............................ 2
DIAGNOSIS AND TESTING
BATTERY TEMPERATURE SENSOR.......... 8
CHARGING SYSTEM RESISTANCE TESTS..... 5CHARGING SYSTEM...................... 2
CURRENT OUTPUT TEST.................. 8
ON-BOARD DIAGNOSTIC SYSTEM TEST..... 10
REMOVAL AND INSTALLATION
BATTERY TEMPERATURE SENSOR......... 11
GENERATOR........................... 10
SPECIFICATIONS
GENERATOR RATINGS................... 12
TORQUE.............................. 12
GENERAL INFORMATION
OVERVIEW
The battery, starting, and charging systems oper-
ate with one another, and must be tested as a com-
plete system. In order for the vehicle to start and
charge properly, all of the components involved in
these systems must perform within specifications.
Group 8A covers the battery, Group 8B covers the
starting system, and Group 8C covers the charging
system. Refer to Group 8W - Wiring Diagrams for
complete circuit descriptions and diagrams. We have
separated these systems to make it easier to locate
the information you are seeking within this Service
Manual. However, when attempting to diagnose any
of these systems, it is important that you keep their
interdependency in mind.
The diagnostic procedures used in these groups
include the most basic conventional diagnostic meth-
ods to the more sophisticated On-Board Diagnostics
(OBD) built into the Powertrain Control Module
(PCM). Use of an induction ammeter, volt/ohmmeter,
battery charger, carbon pile rheostat (load tester),
and 12-volt test lamp may be required.
All OBD-sensed systems are monitored by the
PCM. Each monitored circuit is assigned a Diagnos-
tic Trouble Code (DTC). The PCM will store a DTC in
electronic memory for any failure it detects. See the
On-Board Diagnostics Test in Group 8C - Charging
System for more information.
DESCRIPTION AND OPERATION
CHARGING SYSTEM OPERATION
The charging system consists of:
²Generator
²Electronic Voltage Regulator (EVR) circuitry
within the Powertrain Control Module (PCM)
²Ignition switch (refer to Group 8D, Ignition Sys-
tem for information)
²Battery (refer to Group 8A, Battery for informa-
tion)
²Battery temperature sensor
²Voltmeter (refer to Group 8E, Instrument Panel
and Gauges for information)
²Wiring harness and connections (refer to Group
8W, Wiring for information)
The charging system is turned on and off with the
ignition switch. When the ignition switch is turned to
the ON position, battery voltage is applied to the
generator rotor through one of the two field termi-
nals to produce a magnetic field. The generator is
driven by the engine through a serpentine belt and
pulley arrangement.
The amount of DC current produced by the gener-
ator is controlled by the EVR (field control) circuitry,
contained within the PCM. This circuitry is con-
nected in series with the second rotor field terminal
and ground.
PLCHARGING SYSTEM 8C - 1

A battery temperature sensor located on the front
bumper beam is used to sense battery temperature.
This temperature data, along with data from moni-
tored line voltage, is used by the PCM to vary the
battery charging rate. This is done by cycling the
ground path to control the strength of the rotor mag-
netic field. The PCM then compensates and regulates
generator current output accordingly and to maintain
the proper voltage depending on battery tempera-
ture.
All vehicles are equipped with On-Board Diagnos-
tics (OBD). All OBD-sensed systems, including the
EVR (field control) circuitry, are monitored by the
PCM. Each monitored circuit is assigned a Diagnos-
tic Trouble Code (DTC). The PCM will store a DTC in
electronic memory for any failure it detects. See On-
Board Diagnostic System Test in this group for more
information.
GENERATOR
The generator is belt-driven by the engine. It is
serviced only as a complete assembly. If the genera-
tor fails for any reason, the entire assembly must be
replaced.
As the energized rotor begins to rotate within the
generator, the spinning magnetic field induces a cur-
rent into the windings of the stator coil. Once the
generator begins producing sufficient current, it also
provides the current needed to energize the rotor.
The Y type stator winding connections deliver the
induced AC current to 3 positive and 3 negative
diodes for rectification. From the diodes, rectified DC
current is delivered to the vehicle electrical system
through the generator, battery, and ground terminals.
Noise emitting from the generator may be caused
by:
²Worn, loose or defective bearings
²Loose or defective drive pulley
²Incorrect, worn, damaged or misadjusted drive
belt
²Loose mounting bolts
²Misaligned drive pulley
²Defective stator or diode
BATTERY TEMPERATURE SENSOR
The battery temperature sensor is used to deter-
mine the battery temperature. This temperature
data, along with data from monitored line voltage, is
used by the PCM to vary the battery charging rate.
System voltage will be higher at colder temperatures
and is gradually reduced at warmer temperatures.
The sensor is located on the bottom of the battery
tray (Fig. 1).
ELECTRONIC VOLTAGE REGULATOR
The Electronic Voltage Regulator (EVR) is not a
separate component. It is actually a voltage regulat-
ing circuit located within the Powertrain Control
Module (PCM). The EVR is not serviced separately. If
replacement is necessary, the PCM must be replaced.
Operation:The amount of DC current produced
by the generator is controlled by EVR circuitry con-
tained within the PCM. This circuitry is connected in
series with the generators second rotor field terminal
and its ground.
Voltage is regulated by cycling the ground path to
control the strength of the rotor magnetic field. The
EVR circuitry monitors system line voltage and bat-
tery temperature (refer to Battery Temperature Sen-
sor for more information). It then compensates and
regulates generator current output accordingly. Also
refer to Charging System Operation for additional
information.
DIAGNOSIS AND TESTING
CHARGING SYSTEM
When the ignition switch is turned to the ON posi-
tion, battery potential will register on the voltmeter.
During engine cranking a lower voltage will appear
on the meter. With the engine running, a voltage
reading higher than the first reading (ignition in ON)
should register.
The following are possible symptoms of a charging
system fault:
²The voltmeter does not operate properly
²An undercharged or overcharged battery condi-
tion occurs.
Fig. 1 Battery Temperature Sensor
8C - 2 CHARGING SYSTEMPL
DESCRIPTION AND OPERATION (Continued)