E N G L I S H
71
If the voltage drop reading exceeds the maximum
allowable voltage drop, the point of excessive
resistance can be located by checking the voltage
reading at each connection and cable end.
When a sharp decrease in voltage drop is observed,
the cause of the excessive resistance will be located
between that test point and the previous test point.
1. Battery Ground to Engine Block Voltage Drop
Test
This test checks for engine Ground efficiency.
To check voltage drop:
• Set the rotary switch to voltage ( ).
• Touch the Black test probe to the negative (-) battery
post and the Red test probe to the positive (+)
battery post; this reading will be the base voltage
to compare against your test voltage reading.
Move and connect:
• Red test probe to a clean spot on the engine block.
Set:
• RECORD (MAX-MIN-AVG) function on the Meter.
Disable the ignition so the engine doesn’t start and
crank the engine for 4 ~ 5 seconds.
This connection has 2 connectors, 1 wire, 1 Ground
and 1 cable terminal to battery post so a voltage drop
of more than 500mV would indicate a poor Ground
circuit.
Test again after cleaning and inspecting the battery
cable connections and the Ground.
NOTE: Repeat this test when the engine is thoroughly
warmed up. Heat expansion of metal may cause voltage
drop to increase.
2. Negative Chassis Ground Efficiency Test
This test checks for chassis Ground efficiency.
To check voltage drop:
- Set the rotary switch to voltage ( ).
- Touch the Black test probe to the negative (-) battery
post and the Red test probe to the positive (+)
battery post; this reading will be the base voltage
to compare your test voltage reading against.
Connect:
- Black test probe to the negative (-) battery post.
- Red test probe to the point on the fender, fire wall
or vehicle frame where the accessory Ground is
fastened.
Set:
- RECORD (MAX-MIN-AVG) function on the Meter.
Turn:
- All of the accessories (headlights, A/C fan, defroster,
windshield wiper, etc.) On.
Disable the ignition so the engine doesn’t start and
crank the engine for 4~5 seconds.
This connection has 2 connectors, 1 wire 1 Ground and
1 cable terminal to battery post so a voltage drop of
more that 500mV would indicate poor Ground circuit.
Test again after cleaning and inspecting the battery
cable connections and the Ground.
Summary of Contents for UD88
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