Chapter 2: In Vehicle Test
DSS-5000
Test Results - Alternator
Decision
Action
CHARGING
NORMAL
The output from the alternator is normal.
NO OUTPUT
No output detected. Check belts to ensure
alternator is rotating when engine is running.
√
Check all alternator connections including
to the battery. Clean or replace if
necessary and retest.
√
If the belts and connections are in good
working condition, replace alternator or
external voltage regulator.
LOW
OUTPUT
Alternator not providing enough current to
power electrical loads and charge the battery.
√
Check belts to ensure the alternator is
rotating with the engine running.
√
Check alternator connections to and from
the battery. If loose or heavily corroded,
clean or replace the cable and retest.
HIGH
OUTPUT
Alternator voltage to the battery exceeds
normal limits of a functioning regulator.
√
Check for loose and normal ground
connections. If no connection problems
are found, replace the regulator.
The normal high limit of a typical automotive
regulator is 14.5 volts +/–0.5. Refer to the
manufacturer specifications for the correct limit,
which may vary by vehicle type.
Test Results - Diode
Decision
Action
EXCESSIVE
RIPPLE
One or more diodes in the alternator are not
functioning or there is stator damage, which is
shown by an excessive amount of AC ripple
current supplied to the battery.
√
Make sure the alternator mounting is
sturdy and that the belts are in good
shape and functioning properly. If the
mounting and belts are good, replace the
alternator.
OPEN PHASE
Replace the alternator.
OPEN DIODE
SHORTED
DIODE
