Using Electrical Test Equipment - Mazda 1996 626 Service Manual

USING ELECTRICAL TEST EQUIPMENT

Equipment
Used to find open or short cir­
Test light
cuits.
Jumper wire Used to create a tem porary cir­
cuit.
Voltmeter Used to find open or short cir­
cuits by measuring circuit volt­
age.
Ohmmeter Used to find open or short cir­
cuits, to confirm continuity, and
to check sensor resistance.
Ammeter Used to check alternator output,
current supplied to the starter,
and dark current within a circuit.
U
(Dark current is the current
flowing through the circuit when
the ignition switch is at OFF.)
FUNDAMENTAL TROUBLESHOOTING
Purpose
Connect the test light
between the circuit being
measured and ground.
The light will turn on if the
circuit is energized to the
point tested.
Connect the jum per wire
between the terminals of a
circuit to bypass a switch.
Set the range to the specified
voltage.
Connect the positive (+) lead
to where voltage is to be
measured and the negative
(-) lead to ground.
Make sure the ignition switch
is off or the negative (-) bat­
tery cable is disconnected.
Switch the ohmmeter to the
appropriate measuring range.
Set the ohmm eter to zero
before connecting the leads
to the connector.
Set the range to the desired
amperage.
Touch the positive (+) lead to
the power-side terminal and
the negative (-) lead to the
ground-side terminal.
Use
Use test lights with
1.4W or 3.4W bulbs or light-
emitting diodes (LEDs).
Using large-capacity bulbs
may damage the CPU.
Do not connect the power
side directly to ground.
This may burn the harness
or damage electrical compo­
nents.
Connect the voltmeter in
parallel with the circuit.
Use the service hole when
measuring the voltage at the
data link connector.
Tie a thin wire to the positive
(+) lead to access narrow
terminals.
If current is flowing through
the circuit, the ohmmeter
could be burned.
Connect the ammeter in
series with the circuit. The
ammeter may be burned if it
is connected in parallel.
Gl
Handling
1 2 V
G I-17