Battery Cables Diagnosis - Jeep 200 Cherokee Service Manual

8A - 14 BATTERY
DIAGNOSIS AND TESTING (Continued)
Module
Radio
Audio Power
Amplifier
Central Timer Module
(CTM)
Powertrain Control
Module (PCM)
ElectroMechanical
Instrument Cluster
(EMIC)
Combination Flasher
(2) Determine that the under-hood lamp is operat-
ing properly, then disconnect the lamp wire harness
connector or remove the lamp bulb.
(3) Disconnect the battery negative cable.
(4) Set an electronic digital multi-meter to its
highest amperage scale. Connect the multi-meter
between the disconnected battery negative cable ter-
minal clamp and the battery negative terminal post.
Make sure that the doors remain closed so that the
illuminated entry system is not activated. The multi-
meter amperage reading may remain high for up to
three minutes, or may not give any reading at all
while set in the highest amperage scale, depending
upon the electrical equipment in the vehicle. The
multi-meter leads must be securely clamped to the
battery negative cable terminal clamp and the bat-
tery negative terminal post. If continuity between the
battery negative terminal post and the negative cable
terminal clamp is lost during any part of the IOD
test, the electronic timer function will be activated
and all of the tests will have to be repeated.
(5) After about three minutes, the high-amperage
IOD reading on the multi-meter should become very
low or nonexistent, depending upon the electrical
equipment in the vehicle. If the amperage reading
remains high, remove and replace each fuse or circuit
breaker in the Power Distribution Center (PDC) and
then in the Junction Block (JB) one at a time (refer
to Power Distribution Center and Junction
Block in the index of this service manual for the
location of complete PDC and JB fuse and circuit
breaker identification contained in the wiring dia-
grams) until the amperage reading becomes very low,
or nonexistent. This will isolate each circuit and
identify the circuit that is the source of the high-am-
perage IOD. If the amperage reading remains high
after removing and replacing each fuse and circuit
Electronic Module Ignition-Off Draw (IOD)
Time Out?
(If Yes, Interval and Wake-Up Input)
No
No
No
No
No
No
milliamperes
up to 1
milliampere
milliamperes
0.95 milliampere
0.44 milliampere
0.08 milliampere
breaker, disconnect the wire harness from the gener-
ator. If the amperage reading now becomes very low
or nonexistent, refer to Charging System in the
index of this service manual for the location of the
proper charging system diagnosis and testing proce-
dures. After the high-amperage IOD has been cor-
rected, switch the multi-meter to progressively lower
amperage scales and, if necessary, repeat the fuse
and circuit breaker remove-and-replace process to
identify and correct all sources of excessive IOD. It is
now safe to select the lowest milliampere scale of the
multi-meter to check the low-amperage IOD.
CAUTION: Do not open any doors, or turn on any
electrical accessories with the lowest milliampere
scale selected, or the multi-meter may be damaged.
(6) Observe the multi-meter reading. The low-am-
perage IOD should not exceed twenty-five milliam-
peres (0.025 ampere). If the current draw exceeds
twenty-five milliamperes, isolate each circuit using
the fuse and circuit breaker remove-and-replace pro-
cess in Step 5. The multi-meter reading will drop to
within the acceptable limit when the source of the
excessive current draw is disconnected. Repair this
circuit as required; whether a wiring short, incorrect
switch adjustment, or a component failure is at fault.
BATTERY CABLES
DIAGNOSIS
A voltage drop test will determine if there is exces-
sive resistance in the battery cable terminal connec-
tions or the battery cables. If excessive resistance is
found in the battery cable connections, the connec-
tion point should be disassembled, cleaned of all cor-
rosion or foreign
Following reassembly, check the voltage drop for the
IOD After Time
IOD
Out
1 to 3
N/A
N/A
4.75
N/A
N/A
N/A
N/A
material, then reassembled.
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