Page 201
291-10
Turbocharger
Fig. 19. Turbocharger oil supply and return pipes.
APC COMPONENT TESTING
Page 202
Electrical System-General
300-1
300 Electrical System -General
General
Voltage and Polarity
Wiring, Fuses, and Relays
Electrical System Safety Precautions
Electrical Test Equipment
Wiring Diagrams
Wiring Codes and Abbreviations
Using the Wiring Diagrams
Electrical Troubleshooting
Checking for Voltage and Ground
300-1
300-1
300-1
300-1
300-2
300-2
300-2
300-4
To measure voltage
To check for a voltage drop
Checking for Continuity
Checking for Short Circuits
To check for a short
circuit using an ohmmeter
To check for a short circuit
using a voltmeter
300-6
300-6
300-7
300-7
300-7
300-8
TABLES
300-4
300-4
a. Terminal and Circuit Numbers
b. Market Codes
300-3
300-4
.................;:;:;:::
GENERAL
A brief description of the principal parts of the electrical system is presented here. Also covered here are general electrical system troubleshooting tips as well as instructions on
using the Saab wiring diagrams.
Voltage and Polarity
Saab electrical systems are 12-volt direct current (DC) negative-ground systems. A voltage regulator controls the system
voltage at approximately the 12-volt rating of the battery. All
circuits are grounded by direct or indirect connection to the
negative (-) terminal of the battery. A number of ground connections throughout the car connect the wiring harness to
chassis ground. These circuits are compfeted by the battery
cable or ground strap between the body and the battery negative (-) terminal.
Wiring, Fuses, and Relays
Nearly all parts of the wiring harness connect to components of the electrical system with keyed, push-on connectors
that lock into place. Notable exceptions are the heavy battery
cables and the alternator wiring. The wiring is color-coded for
circuit identification.
With the exception of the battery charging system, all electrical power is routed from the ignition switch or the battery
through the fuse/relay panel, located in the right side of the engine compartment. Fuses prevent excessive current from
damaging components and wiring. Fuses are color coded to
indicate their different current capacities.
Fuse rating and color
Red
Blue
Yellow
Green
10 amp
15 amp
20 amp
30 amp
The relays are electromagnetic switches that operate on
low current to switch a high-current circuit on and off. Many of
the relays are mounted on the fuse/relay panel in the engine
compartment, although later models are equipped with additional auxiliary relay panels. For information on relay and fuse
locations, see 371 Wiring Diagrams, Fuses and Relays.
Electrical System Safety Precautions
Please read the following warnings and cautions before doing any work on your electrical system.
WARNING
• Some of the cars covered by this manual are equipped with
a Supplemental Restraint System (SRS) that automatically
deploys an airbag. The airbag unit uses an explosive device
to electrically ignite a powerful gas. On cars so equipped, any
work involving the steering wheel and SRS system should
only be performed by an authorized Saab dealer. Perfonning
repairs without disarming the SRS may cause serious personal injury.
• On cars equipped with SRS (airbag) the ignition switch must
be in the lock position before replacing fuses. If fuse no. 7 is
removed with the ignition switch on, an SRS fault will be detected. If the SRS waming light comes on, see an authorized
Saab dealer.
GENERAL
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df
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:::::::::::::::::':':';'"
Page 203
300-2
Electrical System-General
WARNING
• The ignition system of the car operates at lethal voltages.
People with pacemakers or weak hearts should not expose
themselves to the ignition system. Extra caution must be taken when working on the ignition system or when servicing the
engine while it is running or the key is on. See 340 Ignition
System for additional ignition system warnings and cautions.
• Before operating the starter without starting the engine (as
when making a compression test), disable the ignition system
as described in 340 Ignition System.
• Keep hands, clothing and other objects clear of the radiator
cooling fan when working on a wann engine. The fan may
start at any time, even when the ignition is switched off.
CAUTiON
• Always tum off the engine and remove the negative (-) battery cable before removing any electrical components.
• Connect and disconnect ignition system wires, multiple connectors, and ignition test equipment leads only while the ignition is off.
• Do not disconnect the battery while the engine is running.
• Do not quick-charge the battery (for boost starting) for longer
than one minute, and do not exceed 16.5 volts at the battery
with the boosting cables attached. Wait at least one minute
before boosting the battery a second time.
• Do not use a test lamp that has a nonnal incandescent bulb
to test circuits containing electronic components. The high
electrical consumption of these test lamps may damage the
components.
• Many of the solid-state modules are static sensitive. Static
discharge will pennanently damage them. Always handle the
modules using proper static prevention equipment and techniques.
• To avoid damaging harness connectors or relay panel sockets, use jumper wires with flat-blade connectors that are the
same size as the connector or relay tenninals.
• Always switch a test meter to the appropriate function and
range before making test connections.
• Do not try to start the engine of a car which has been heated
above 176°F (80°C), (for example, in a paint drying booth) until allowing it to cool to nonnal temperature.
Electrical Test Equipment
Many of the electrical tests described in this manual call for
measuring voltage, current or resistance using a digital multimeter (DMM). Digital meters are preferred for precise measurements and for electronics work because they are
generally more accurate than analog meters. The numerical
display is also less likely to be misread, since there is no needle position to be misinterpreted by reading at an angle.
An LED test light is a safe, inexpensive tool that can be
used to perform many simple electrical tests that would otherwise require a multi meter. The LED indicates when voltage is
present between any two test-points in a circuit.
CAUTION
• Choose test equipment carefully. Use a meter with at least
10 megohm input impedance, or an LED test light. An analog
meter (swing-needle) or a test light with a nonnal incandescent bulb may draw enough current to damage sensitive electronic components.
• An ohmmeter must not be used to measure resistance on
solid state components such as control units or time delay relays.
• Always disconnect the battery before making resistance
(ohm) measurements on the circuit.
WIRING DIAGRAMS
The wiring diagrams shown in 371 Wiring Diagrams, Fuses and Relays have been specially designed to enable quick
and efficient diagnosis and troubleshooting of electrical malfunctions.
Each electrical sub-system, such as the ignition system, the
hazard warning lights, etc., is described individually and a
separate wiring diagram is shown for each sub-system on the
car. Each wiring sub-system consists of a spread that includes a brief description of the circuit operation, fault tracing,
a list of all the components used in the circuit along with their
location in the car, and the wiring diagram(s) applicable to that
circuit.
• Disconnect the battery before doing any electric welding on
the car.
Wiring Codes and Abbreviations
• Do not tow a car suspected of having a defective ignition
system without first disconnecting the ignition control unit.
A tremendous amount of information is included in each
wiring diagram if you know how to read them. For example,
you will notice that all electrical components, connectors, fuses, and ground locations are idenhfied using a unique number. Each of these numbers corresponds to a particular part in
the circuit. A complete listing of these component numbers,
their identifications and locations is given in 371 Wiring Diagrams, Fuses and Relays.
• Do not wash the engine while it is running, or anytime the ignition is switched on.
WIRING DIAGRAMS
Page 204
Electrical System-General
All wire colors in the diagrams are abbreviated. Combined
color codes indicate a multi-colored wire. For example the
code BURD indicates a Blue wire with a Red stripe. Wire color
abbreviation are listed below. Immediately following the wire
color is the nominal cross-sectional area of the wire given in
mm2 .
300-3
Table a. Terminal and Circuit Numbers (continued)
Number
Circuit description
50 or +50
Supplies power from battery to starter solenoid
when ignition switch is in START position only
+54
Originates at ignition switch. Supplies power
when ignition switch is in the RUN position only
85
Ground side (-) of relay coil
86
Power-in side (+) of relay coil
87
Relay change-over contact
-
NOTE
Sometimes the color of an installed wire may be different than
the one on the wiring diagram. Don't be concemed, just be
sure to confinn that the wire connects to the proper tenninals.
D
I
I
Wire color codes
BL or BU . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. Blue
BR or BN
Brown
GL or YE
Yellow
GN
Green
GR or GY
Gray
OG
RA or PK
Orange
Pink
RD
Red
SV or BK. . . . . . . . . . . . . . . . . . . . . . . . . . . .. Black
VL
Violet
VT or WH
White
Most terminals are identified by numbers on the components and harness connectors. The terminal numbers for major electrical connections are shown in the diagrams. Though
many terminal numbers appear only once, several other numbers appear in numerous places throughout the electrical system and identify certain types of circuits. Several of the most
common circuit numbers are listed below in Table a.
Table a. Terminal and Circuit Numbers
Number
Circuit description
1
Low voltage switched (1) tenninal of coil
4
High voltage center tenninal of coil
+X
Originates at ignition switch. Supplies power
when the ignition switch is in the PARK, RUN, or
START position
S
Originates at ignition switch. Supplies power
whenever the key is in the ignition switch.
(power in LOCK, PARK, RUN, or START
position)
15 or +15
Originates at ignition switch. Supplies power
when ignition switch is in RUN or START
position
30 or +30
Battery positive (+) voltage. Supplies power
whenever battery is connected. (Not dependent
on ignition switch position, unfused)
31
Ground, battery negative (-) tenninal
~Ite':lator waming light and field energizing
circuit
Additional abbreviations shown in the wiring diagrams are
given below.
Abbreviations
ABS
AC
AIC
APC
AUT
CAB
CC
CONV
ECU
EZK
I
LH
LHD
LHF
LH R
LHS
antilock brakes
air conditioning
automatic idle control
automatic performance
control (turbo models)
automatic transmission
cabriolet (convertible)
cruise control
convertible
electronic control unit
electronic ignition with knock control
fuel injection engine
fuel injection system
left hand drive
left hand, front
left hand, rear
left hand, side
M
. . . . . . . . . . . . . .. designation for model year,
i.e. M89 for 1989 model
MAN
manual transmission
passenger
P
RHO
right hand drive
RH F. . . . . . . . . . . . . . . . . . . . . . . . . right hand, front
RH R
RHS
right hand, rear
right hand, side
SRS
supplemental restraint system
Airbag (see warnings in text)
T . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. turbo
TSI
timing service instrument (test socket)
2-D . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-door sedan
3-D
3-door hatchback
4-0 .. . . . . . . . . . . . . . . . . . . . . . . . . . 4-door sedan
US
Cars for sale in the United States
CA
Cars for sale in Canada
UC
Cars for sale in California
continued
WIRING DIAGRAMS
Page 205
-300-4
Electrical System-General
CAUTION
Many of the wiring diagrams are applicable to cars delivered
to otherworld markets served by Saab. At times, there may be
certain parts of the diagram that are applicable only to these
markets. This manual covers only Saab cars delivered to the
United States (US), Califomia (UC), and Canada (CA). Abbreviations other than US, UC, and CA found on a particular diagram should be ignored. For example the abbreviation "ME"
is for cars sold in the Middle East. Table b is a complete list of
the market codes.
Market
Market
codes
AT
Austria
~ f France
AU
Australia
GB
BE
Belgium
GR
CA
Canada
IS
CH
Switzerland
IT
Italy
DE
Germany
JP
Japan
I
Market
i
r----
Four things are required for current to flow in any electrical
circuit: a voltage source, wires or connections to transport the
voltage, a consumer or device that uses the electricity, and a
connection to ground. Most problems can be found using only
a digital multimeter (volt/ohm/amp meter) to check for voltage
supply, for breaks in the wiring (infinite resistance/no continuity), or for a path to ground that completes the circuit.
Electric current is logical in its flow, always moving from the
voltage source toward ground. Keeping this in mind, electrical
faults can be located through a process of elimination. When
troubleshooting a complex circuit, separate the circuit into
smaller parts. The general tests outlined below may be helpful
in finding electrical problems. The information is most helpful
when used with the wiring diagrams.
Table b. Market Codes
Market
codes
ELECTRICAL TROUBLESHOOTING
Great Britain
I
I
Be sure to analyze the problem. Use the wiring diagrams to
determine the most likely cause of the problem. Get an understanding of how the circuit works by following the circuit from
ground back to the power source.
Greece
Iceland
You will find the problem if you follow a simple and logical
step-by-step procedure. Test portions of the circuit at one
time, starting with the area or component most likely to be at
fault. Test first at points that you can reach most easily. When
you find the cause of the problem, make the repair. Use appropriate tools and procedures. As a final check, test the functions of the circuit that you worked on.
I
DK
Denmark
ME
Middle East
ES
Spain
NL
Netherlands
EU
Europe
NO
Norway
FE
Far East
SE
Sweden
FI
Finland
US
USA
-
Using the Wiring Diagrams
An example of a wiring diagram is shown below together
with an explanation of the symbols used in the diagram. See
Fig.1.
NOTE
• Unless specified otherwise, switches and relays are shown
in the rest or de-energized position.
• Throughout the wiring diagrams, a fuse is shown together
with the designation 22A. This 22A code is the component
number for the fuse holder in the fuse/relay panel and should
not be confused with the fuse rating or the fuse position.
• Designations such as +30, +15, +54 are positive voltage
supplies, usually found at the top of each circuit. Each number
represents when voltage is present in the circuit. For example,
+30 is live at all times (unfused) and +15 is live when the key
is in the run or start position. See above for a listing of the
common terminal and circuit numbers.
ELECTRICAL TROUBLESHOOTING
When making test connections at connectors and components, use care to avoid spreading or damaging the connectors or terminals. Some electrical tests may require jumper
wires to temporarily bypass components or connections in the
wiring harness. When connecting jumper wires, use blade
connectors at the wire ends that match the size of the terminal
being tested. The delicate internal contacts are easily spread
apart, and this can cause intermittent or faulty connections
that can lead to more problems.
Checking for Voltage and Ground
Checking for the presence of voltage or ground is usually
the first step in troubleshooting a problem circuit. When
checking for voltage, a digital voltmeter or LED test light
should be used. for example, if a parking light does not work,
check for voltage at the bulb socket will quickly determine if
the circuit is functioning properly or if the bulb itself is faulty. If
voltage and ground are found at the socket, then the bulb is
most likely faulty.
Another valuable troubleshooting technique is a voltage
drop test This is a good test to make if current is flowing
through the circuit, but the circuit is not operating correctly.
Sluggish wipers or dim headlights are examples of this. A voltage drop test will help to pinpoint a corroded ground strap or a
faulty switch. Normally, there should be less than 1 volt drop
across most wires or closed switches. A voltage drop across a
connector or short cable should not exceed 0.5 volts.
Page 206
Electrical System-General
Positive supply +54
(live with ignition
key in run position
only)
Number indicates
component (1 is the
battery. See complete list at end of
wiring diagrams)
Schematic of relay
(component 229 is
the system relay)
~~L-~
~~9"
Fuse in main fuse!
relay panel
(component 22a)
C
Positive supply +15
(live with ignition
key in run or start
position only)
~,
~l4·1~.
~,
1,:,
+15
I
_ _------l 75
R"-C>'-"
7
229
211
Fuse in position 22
(component 22a)
12J'"
GN/IIT10
Connector 1528
(this is a 29-pin
connector)
159
+-15
Wire color (green!
violet) and wire size
(1.0 mm 2)
Dashed line
indicates partial
view of instrument
panel
Schematic symbol
for solenoid
(component 206 is
fuel injector)
Schematic symbol
for light bulb
2C'0
LH control unit
(component 200).
Solid state components are usually
empty in center
200
~ '.,'
~ 202
~
201
), it ",7
1"T7:.
1"T7: :.
~i
-~:':,
GR/RO 2 ~
Schematic symbol
of ground point (201
is on the engine)
Fig. 1.
Diamond shape
indicates a splice
in the wiring
hamess
Schematic symbol
for switch (component 203 is a throttle
switch)
Connector 152a,
terminal 25 in
connector
1:,'2A
'"
Abbreviations for
other markets (ME
for Middle East and
FE for Far East)
i
~~L.-J
2~
Schematic symbol
for motor
(component 101 is
fuel supply pump)
300-5
Schematic symbol
for a temperature
sensor (component
202 is the engine
temperature sensor)
Indicates a
connector not
connected to
another connector
(component 204 is a
tesl connector for
the LH fuel injection
system)
Connector 59
(2-pin connector)
showing wires in
terminal 1 and 2
Example of how to read Saab wiring diagrams.
ELECTRICAL TROUBLESHOO TlNG
Page 207
300-6
Electrical System-General
-,
The wires, connectors, and switches that carry current are
designed with very low resistance so that current flows with a
minimum loss of voltage. A voltage drop is caused by higher
than normal resistance in a circuit. This additional resistance
actually decreases or stops the flow of current. A voltage drop
can be noticed by problems ranging from dim headlights to
sluggish wipers. Some common sources of voltage drops are
faulty wires or switches, dirty or corroded connections or contacts, and loose or corroded ground wires and ground connections.
Voltage drop can only be checked when current is running
through the circuit, such as by operating the starter motor or
turning on the headlights. Making a voltage drop test requires
measuring the voltage in the circuit and comparing it to what
the voltage should be. Since these measurements are usually
small, a digital voltmeter should be used to ensure accurate
readings. If a voltage drop is suspected, turn the circuit on and
measure the voltage at the circuit's load.
from Battery
I
+
I
I
Fuse box
I
I
/;f1I'------... .....................
/
""
---""-. .......
Voltmeter
I
Switch
.......
""
I
""- ,,
II
No voltage
Load
NOTE
• A voltage drop test is generally more accurate than a simple
resistance check because the resistances involved are often
too small to measure with most ohmmeters. For example, a
resistance as small as 0.02 ohms would results in a 3 Volt
drop in a typical 150 amp starter circuit. (150 amps x 0.02
ohms =3 volts).
Fig. 2. Voltmeter being used to check for voltage.
• Keep in mind that voltage with the key on and voltage with
the engine running are not the same. With the ignition on and
the engine off (battery voltage), voltage should be approximately 12.6 volts. With the engine running (charging voltage),
voltage should be approximately 14.0 volts. Measure voltage
at the battery with the ignition on and then with the engine running to get exact measurements.
from Battery
87382
2. Connect the voltmeter negative lead to the other end of
the cable or switch being tested. See Fig. 3.
~-
+
To measure voltage
1. Connect the voltmeter negative lead to a reliable
ground point on the car. The negative (-) battery terminal is always a good a ground point.
+
Voltmeter
~
\.
Switch
e
2. Connect the voltmeter positive lead to the point in the
circuit you wish to measure. See Fig. 2. If a reading is
obtained, current is flowing through the circuit.
Load
NOTE
The voltage reading should not deviate more than 1 volt less
than the voltage at the battery. If the voltage is less than this,
there is probably a fault in the circuit, such as a corroded connector or a loose ground wire.
-
-
87383
_
-
Fig. 3. Voltmeter being used to check for voltage drop.
To check for a voltage drop
1. Connect the voltmeter positive lead to the positive (+)
battery terminal or a positive power supply close to the
battery source.
ELECTRICAL TROUBLESHOOTING
3. With the power on and the circuit working, the meter
shows the voltage drop (the difference between the two
points). This value should not exceed 1 volt.
Page 208
Electrical System-General
NOTE
The maximum voltage drop in an automotive circuit, as recommended by the Society of Automotive Engineers (SAE), is
as follows: 0 Volts for small wire connections; 0.1 Volts for
high current connections; 0.2 Volts for high current cables;
and 0.3 Volts for switch or solenoid contacts. On longer wires
or cables, the drop may be slightly higher. In any case, a voltage drop of more than 1.0 Volt usually indicates a problem.
300-7
Brake pedal in rest position
Brake light switch
Checking for Continuity
The continuity test can be used to check a circuit or switch.
Because most automotive circuits are designed to have little
or no resistance, a circuit or part of a circuit can be easily
checked for faults using an ohmmeter. An open circuit or a circuit with high resistance will not allow current to flow. A circuit
with little or no resistance allows current to flow easily.
Brake pedal depressed
Brake light switch
CAUTION
Do not use an analog (swing-needle) ohmmeter to check circuit resistance or continuity on any electronic (solid-state)
components. The intemal power source used in most analog
meters can damage solid state components. Use only a high
quality digital ohmmeter having high input impedance when
checking electronic components.
When checking continuity, the ignition should be off. On circuits that are powered at all times, the battery should be disconnected. Using the appropriate wiring diagram, a circuit can
be easily tested for faulty connections, wires, switches, relays, and engine sensors by checking for continuity. Fig. 4
shows continuity test being made on a brake light switch.
Checking for Short Circuits
A short circuit is exactly what the name implies. The circuit
takes a shorter path than it was designed to take. The most
common short that causes problems is a short to ground
where the insulation on a positive (+) wire wears away and the
metal wire is exposed. When the wire rubs against a metal
part of the car or other ground source, the circuit is shorted to
ground. If the exposed wire is live (positive battery voltage), a
fuse will blow and the circuit may possibly be damaged.
Shorts to ground can be located with an ohmmeter or a voltmeter. Short circuits are often difficult to locate and may vary
in nature. Short circuits can be found using a logical approach
based on the current path.
87437
Fig. 4.
Brake light switch being tested for continuity. With brake pedal in rest position (switch open) there is no continuity (infinite
ohms). With the pedal depressed (switch closed) there is continuity (zero ohms).
CAUTION
• On circuits protected with large fuses (25 amp and greater),
the wires or circuit components may be damaged before the
fuse blows. Always check for damage before replacing fuses
of this rating.
• When replacing blown fuses, use only fuses having the correct rating. Always confirm the correct fuse rating printed on
the fuse/relay panel cover.
To check for a short circuit using an ohmmeter
1. Remove the blown fuse from the circuit and disconnect
the cables from the battery.
2. Disconnect the harness connector from the circuit's
load or consumer.
3. Using an ohmmeter, connect one test lead to the load
side of the fuse terminal (terrninalleading to the circuit)
and the other test lead to ground. See Fig. 5.
4. If there is continuity to ground, there is a short to
ground.
ELECTRICAL TROUBLESHOOTING
Page 209
300-8
Electrical System-General
Battery disconnected
3. Using a voltmeter, connect the test leads across the
fuse terminals. See Fig. 6. Make sure power is present
in the circuit, if necessary turn the key on.
Fuse box
Ohmmeter
from Battery
Short-ci rcuit
to earth
Voltmeter
+
Switch
Fuse box
Sho rt-circuit
to earth
Load disconnected
r1l
I
L
I Load
.J
Switch
Load disconnected
,
1
r
87384
I
L
Fig. 5. Ohmmeter being used to find short circuit.
5. If there is no continuity, work from the wire harness
nearest to the fuse/relay panel and move or wiggle the
wires while observing the meter. Continue to move
down the harness until the meter displays a reading.
This is the location of the short to ground.
Visually inspect the wire harness at this point for any faults.
If no faults are visible, carefully slice open the harness cover
or the wire insulation for further inspection. Repair any faults
found.
To check for a short circuit using a voltmeter
1. Remove the blown fuse from the circuit.
2. Disconnect the harness connector from the circuit's
load or consumer.
ELECTRICAL TROUBLESHOOTING
I
Load
...J
87385
Fig. 6.
Voltmeter being used to find short circuit.
4. If voltage is present at the voltmeter, there is a short to
ground.
5. If voltage is not present, work from the wire harness
nearest to the fuse/relay panel and move or wiggle the
wires while observing the meter. Continue to move
down the harness until the meter displays a reading.
This is the location of the short to ground.
Visually inspect the wire harness at this point for any faults.
I'f no faults are visible, carefully slice open the harness cover
or the wire insulation for further inspection. Repair any faults
found.
Page 210
--Battery
311-1
311 Battery
General
311-1
Battery Testing
311-1
311-1
311-2
Open-Circuit Voltage Test
Load Voltage Testing
GENERAL
The six-cell, 12-volt lead-acid battery capacity is rated by
ampere/hours (Ah) and cold cranking amps (GGA). The Ah
rating is determined by the average amount of current the battery can deliver over time without dropping below a speci'fied
voltage. The GGA rating is determined by the battery's ability
to deliver starting current at 0° (-18°G). The original battery installed is rated at 62 Ah and is located in the engine
compartment, beh ind the right headlight assembly.
Maintenance consists of keeping the battery and terminals
clean and keeping the connections tight. After cleaning, a light
coating of petroleum jelly should be spread on the terminals.
Inspect the battery cables for chafing and deterioration of the
insulation due to high heat.
For general information on troubleshooting electrical systems
see 300 Electrical System--General. For information on battery wiring see 371 Wiring Diagrams, Fuses and Relays.
WARNING
• Wear goggles, rubber gloves, and a rubber apron when
working with battery electrolyte. Electrolyte contains sulfuric
acid and can cause skin irritation and burning. If electrolyte is
spilled on your skin or clothing, flush the area at once with
large quantities of water. If electrolyte gets into your eyes,
bathe them with large quantities of clean water for several
minutes and call a physician.
• Batteries that are being charged or are fUlly charged give off
explosive hydrogen gas. Keep sparks and open flames away.
Do not smoke.
Battery Charging
311-2
TABLES
a. Open-Circuit Voltage and Battery Charge
b. Battery Charging Specifications
311-1
311-2
CAUTION
• Do not quick-charge the battery (for boost starting) for longer
than one minute, and do not exceed 16.5 volts at the battery
with the boosting cables attached. Wait at least one minute
before boosting the battery a second time.
• Always disconnect the negative (-) battery cable first and reconnect it last. Cover the battery post with an insulating material whenever the terminal is removed.
• When boost starting the car using jumper cables, be careful
not to reverse the battery connections. Even a momentary
connection will damage the altemator.
BATTERY TESTING
Battery testing determines the state of battery charge. The
most common methods are open-circuit and load voltage testing. Batteries that have filler caps can also be tested by checking the specific gravity of the electrolyte. The specific gravity
test checks the amount of acid in the electrolyte as an indication of battery charge. Inexpensive specific gravity testers are
available at most auto supply stores.
Open-Circuit Voltage Test
An open-circuit voltage test checks battery voltage by connecting an accurate digital voltmeter to the battery posts after
disconnecting the battery ground cable. Before making an
open-circuit voltage test on a battery, first load the battery with
15 amps for one minute, for example by turning on the headlights without the engine running. Open-circuit voltage levels
and their corresponding percentages of charge are in Table a.
CAUTION
• Do not disconnect the battery when the engine is running.
The alternator will be damaged.
Table a. Open-Circuit Voltage and Battery Charge
Open-circuit voltage
State of charge
• Replace batteries if the case is cracked or leaking. Electrolyte can damage the car. If electrolyte is spilled, clean the area
with a solution of baking soda and water.
12.6 V or more
Fully charged
• Always allow a frozen battery to thaw before attempting to
recharge it.
12.4 V
75% charged
12.2 V
I 50% charged
12.0 V
I 25% charged
11.7 V or less
Fully discharged
• Always disconnect the battery terminals during battery recharging. This will prevent damage to solid-state components.
BA TTERY TESTING