Jeep Cherokee XJ 1999 Manual - page 12
the ignition switch in the Start position. Observe the
voltmeter. If the reading is above 0.2 volt, clean and
tighten the battery cable connection at the solenoid.
Repeat the test. If the reading is still above 0.2 volt,
replace the faulty battery positive cable.
(4) Connect the voltmeter to measure between the
battery negative terminal post and a good clean
ground on the engine block (Fig. 13). Rotate and hold
the ignition switch in the Start position. Observe the
voltmeter. If the reading is above 0.2 volt, clean and
tighten the battery negative cable attachment on the
engine block. Repeat the test. If the reading is still
above 0.2 volt, replace the faulty battery negative
cable.
IGNITION-OFF DRAW TEST
The term Ignition-Off Draw (IOD) identifies a nor-
mal condition where power is being drained from the
battery with the ignition switch in the Off position. A
normal vehicle electrical system will draw from five
to twenty-five milliamperes (0.005 to 0.025 ampere)
with the ignition switch in the Off position, and all
non-ignition controlled circuits in proper working
order. The twenty-five milliamperes are needed to
enable the memory functions for the Powertrain Con-
trol Module (PCM), digital clock, electronically tuned
radio, and other modules which may vary with the
vehicle equipment.
A vehicle that has not been operated for approxi-
mately twenty days, may discharge the battery to an
inadequate level. When a vehicle will not be used for
twenty days or more (stored), remove the IOD fuse
from the Power Distribution Center (PDC). This will
reduce battery discharging.
Excessive IOD can be caused by:
•
Electrical items left on
•
Faulty or improperly adjusted switches
•
Faulty or shorted electronic modules and compo-
nents
•
An internally shorted generator
•
Intermittent shorts in the wiring.
If the IOD is over twenty-five milliamperes, the
problem must be found and corrected before replac-
Fig. 10 Test Battery Negative Connection
Resistance - Typical
Fig. 11 Test Battery Positive Connection Resistance
- Typical
Fig. 12 Test Battery Positive Cable Resistance -
Typical
Fig. 13 Test Ground Circuit Resistance - Typical
8A - 12
BATTERY
XJ
DIAGNOSIS AND TESTING (Continued)