Chrysler RAM TRUCK 2500 1994 Service Manual page 319

8A - 4 ELECTRICAL •
more) before the battery is tested or returned to use.
Refer to Abnormal Battery Discharging for more in­
formation.
YELLOW OR B R I G H T COLOR
A yellow or bright color indicates electrolyte level
in the battery is below test indicator (Fig. 5). Water
can not 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
Generator Test Procedures i n this group.
WARNING: DO NOT ATTEMPT T O C H A R G E , T E S T ,
OR A S S I S T B O O S T B A T T E R Y WHEN Y E L L O W OR
BRIGHT C O L O R IS V I S I B L E IN T E S T INDICATOR.
P E R S O N A L INJURY MAY O C C U R .
TEST 1NDICATORESTATE OF CHARGE
71 CO/
o
REPLACE BATTERY 71
i >
o
REPLACE BATTERY
IBl
^i ^ ^^^^^^^^
Jt
...
(1 \ w / • "
Hi
GREEN
BLACK YELLOW
898A-3
Fig. 5 Test Indicator Sight Glass
ABNORMAL BATTERY DISCHARGING
(1) Corroded battery posts and terminals.
(2) Loose or worn generator drive belt.
(3) Electrical loads that exceed the output of the
charging system due to equipment or accessories in­
stalled after delivery.
(4) Slow driving speeds (heavy traffic conditions) or
prolonged idling with high-amperage draw systems
in use.
(5) Defective electrical circuit or component caus­
ing excess IOD. Refer to Ignition-Off Draw Diagnosis
in this group.
(6) Defective charging system.
(7) Defective battery.
IGNITION-OFF DRAW (IOD) DIAGNOSIS
Ignition-off draw refers to power being drained
from the battery with the ignition switch turned off.
A normal vehicle electrical system will draw from 5
to 20 milliamps. This is with the ignition switch i n
the OFF position, and all non-ignition controlled cir­
cuits i n proper working order. A vehicle that has not
been operated for approximately 20 days, may dis­
charge the battery to an inadequate level. Battery
drain should not exceed approximately 20 MA (20
milliamps = 0.020 amps).
The 20 MA are needed to supply PCM memory, dig­
ital clock memory, and ETR (electronically tuned ra­
dio) memory.
Excessive battery drain is caused by items left
turned on, internally shorted generator, or intermit­
tent short i n wiring.
I f IOD is over 20 milliamperes, the defect must be
found and corrected before replacing a battery. I n
most cases the battery can be charged and returned
to service.
When a vehicle will not be used for 20 days or
more (stored), remove IOD fuse from the fuseblock
module to reduce battery discharging.
T E S T
PROCEDURE
When testing a diesel-equipped vehicle (dual
batteries), do not check IOD between batteries.
One battery may be at a higher state-of-charge
than the other, which will cause a high IOD be­
tween the batteries only. Remove negative ca­
ble from passenger side battery negative post
prior to performing the I O D Test Procedures
outlined below.
Testing for higher amperage IOD must be per­
formed first to prevent damage to most milli-
amp meters.
Verify that all electrical accessories are OFF. Turn
off all lamps, remove ignition key, and close all doors.
I f the vehicle is equipped with electronic accessories
(illuminated entry, high line radio), allow the systems
to automatically shut off (time out), up to 3 minutes.
(1) Determine that the underhood lamp is operat­
ing properly, then disconnect or remove bulb.
(2) Disconnect negative cable from battery.
(3) Connect a typical 12-volt test lamp (low watt­
age bulb) between the negative cable clamp and the
battery negative terminal.
The test lamp may light brightly for up to 3 min­
utes, or may not light at all (depending on the elec­
trical equipment). The term brightly being used
throughout the following tests, implies the brightness
of the test lamp will be the same as i f i t were con­
nected across the battery.
The test lamp must be securely clamped to the neg­
ative cable and battery terminal. I f the test lamp be­
comes disconnected during any of the IOD test, the
electronic timer function will be activated and all
tests must be repeated.
(4) After 3 minutes, the test lamp should turn OFF
or be DIMLY l i t (depending on the electrical equip­
ment). I f the test lamp remains brightly l i t , do not
disconnect i t . Remove each fuse or circuit breaker
(refer to Group 8 - Wiring Diagrams) until test lamp
is either OFF or DIMLY lit. This will eliminate the
higher amperage draw.
I f test lamp is still bright after disconnecting each
fuse and circuit breaker, disconnect the wiring har­
ness from the generator. Refer to Generator Test Pro­
cedures in this group. Do not disconnect the test lamp.
After higher amperage IOD has been corrected, low
amperage IOD may be checked.