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１１
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circuit or component creating resistance.
The resistance decreases the amount of voltage available. The bulb will not
light or the motor will not turn if the voltage is too low.
Maximum Voltage Drop
Maximum voltage drop should not be more than 0.1 volt per
wire, ground, connection, switch or solenoid.
What should be tested?
Each wire, ground, connection, switch solenoid and the complete circuit should
be tested. Each connection point is a potential source of increased resistance.
Voltage Drop Testing
[1] Negative (-) Engine Ground
This test checks for engine ground efficiency.
·
Set the rotary switch to
Voltage.
·
Touch the positive (+)
lead to the positive (+)
battery post and the
negative (-) lead to the
negative (-) battery
post.
Note
the
reading
„
this will be
the base voltage to
compare
your
test
voltage
reading
against.
·
Connect the positive
(+) lead to a clean
spot on the engine
block.
·
Connect the negative (-) lead to the negative battery post.
·
Disable the ignition so the engine doesn
’t start; crank the engine for 2-3
seconds.
The example shown has 2 connectors, 1 wire, 1 ground and 1 terminal to
battery post. A voltage drop of more than 0.5 volts would indicate a poor ground
circuit.
Clean and inspect the battery cable connections test and the ground; test
again.
Important:
Repeat this test when the engine is thoroughly warmed up. Heat
expansion of metal may cause resistance to increase.
[2] Negative (-) Chassis Ground
This test checks for chassis ground efficiency.
·
Set the rotary switch to
Voltage.
·
Establish the base voltage that you will compare test voltage against (see
base voltage, Volt Drop Test [1] ).
·
Connect the positive (+) lead to the point on the fender, fire wall or vehicle
frame where the accessory ground is fastened .
·
Connect the negative (-) lead to the negative battery terminal.
·
Turn all of the accessories ON (bright lights, A/C fan
–high ,rear window
defroster, windshield wipers ,etc.).
·
Disable the ignition so
the engine doesn’t start ; crank the engine for 2-3
seconds .
The example shown has 2 connectors, 1 wire , 1ground and 1 terminal to
battery post. A voltage drop of more than 0.5 volts would indicate a poor ground
circuit .
Clean and inspect the battery cable connections and the ground ; test again .
