M2/M3 BFV: HULL POWER DIST SYSTEM - OD1606 - LESSON 2/TASK 1
in the 20000
OHMS
per
volt
do
column
on
the
left
side
of
the
Make the do voltage test by connecting the black probe to the
negative (ground) side of the circuit being tested. Connect the red
probe to the positive side of the circuit at the point where the
voltage is being measured. All contact points, especially the ground
(vehicle chassis), must be bare metal and clean. Take the dc voltage
reading, using the do scale for the range of the jack to which the
red lead is connected.
If the meter pointer moves in the opposite
direction (tries to move off the scale to the left), reverse the test
leads at the point of contact to correct the polarity;-or, if
preferred, set the FUNCTION switch to 20000/VDC REV to reverse
polarity.
(4) Measuring for High Resistance or a Drop in Voltage. The TS-
352B/U multimeter is useful for performing tests for high resistance
and for drops in voltage. These tests are used to find any voltage
loss caused by a bad part or a faulty connection. Use the procedures
listed below to perform a test for high resistance or a drop in
voltage.
Leave the red (positive) test lead plugged into the 50V jack and the
black lead plugged into the -DC AC jack. The FUNCTION switch should
remain on DIRECT, just as in the dc voltage test.
Place the test
leads across the suspected connection or part, with the red lead on
the plus side and the black lead on the ground side.
What is done next depends on the circuit being tested.
Generally,
the circuit is loaded down by turning on something like the
headlights.
Make the voltage reading on the dc scale ending in 5,
just as in the do voltage test. If only a flicker of the needle is
seen on the 50V scale, move the red lead to the 10V jack and try
again.
If there is still only a flicker of movement, try the 2.5V
jack. A no voltage reading on the DC 25 (2.5) scale means that the
connection or part is good. Any high resistance reading over 1 volt
usually means that the part or connection is bad.
However, in all
tests, abide by the values and methods cited in the appropriate
vehicle TM; in this case, the M2/M3 BFV manuals.
51
Previous Page
