Actron AutoTroubleShooter CP7677 User Manual download pdf (Page 9)

9

Fig. 9

ments, polarity is not important. The

test leads just have to be connected

across the component.

6. Turn multimeter rotary switch to

desired OHM range.

If the approximate resistance is un-

known, start at the largest OHM

range and decrease to the appropri-

ate range as required. (See Setting

the Range on page 6)

7. View reading on display - Note

range setting for correct units.

NOTE: 2KΩ = 2,000Ω; 2MΩ =

2,000,000Ω

If you want to make precise resis-

tance measurements, then subtract

the test lead resistance found in Step

4 above from the display reading in

Step 7. It is a good idea to do this for

resistance measurements less than

10Ω.

Measuring DC Current

This multimeter can be used to measure

DC current in the range from 0 to 10A. If

the current you are measuring exceeds

10A, the internal fuse will blow (see Fuse

Replacement on page 7). Unlike voltage

and resistance measurements where the

multimeter is connected across the com-

ponent you are testing, current measure-

ments must be made with the multimeter

in series with the component. Isolating

current drains and short circuits are some

DC Current applications.

To measure DC Current (see Figs. 10 &

11):

1. Insert BLACK test lead into COM

test lead jack.

2. Insert RED test lead into "10A"

test lead jack or "mA" test lead

jack.

3. Disconnect or electrically open cir-

cuit where you want to measure

current.

This is done by:

• Disconnecting wiring harness.

• Disconnecting wire from screw-on

type terminal.

• Unsolder lead from component if

Red Black

Unknown

Resistance

Measuring Resistance

Resistance is measured in electrical

units called ohms (Ω). The digital multi-

meter can measure resistance from 0.1Ω

to 20MΩ or (20,000,000 ohms). Infinite

resistance is shown with a “1” on the left

side of display (See Setting the Range

on page 6). You can use this multimeter

to do any resistance measurement called

out in the vehicle service manual. Test-

ing ignition coils, spark plug wires, and

some engine sensors are common uses

for the OHMS (Ω) function.

To measure Resistance (see Fig. 9):

1. Turn circuit power OFF.

To get an accurate resistance mea-

surement and avoid possible damage

to the digital multimeter and electrical

circuit under test, turn off all electrical

power in the circuit where the resis-

tance measurement is being taken.

2. Insert BLACK test lead into COM

test lead jack.

3. Insert RED test lead into

test lead jack.

4. Turn multimeter rotary switch to

200

Ω range.

Touch RED and BLACK multimeter

leads together and view reading on

display.

Display should read typically 0.2Ω to

1.5Ω.

If display reading was greater than

1.5Ω, check both ends of test leads

for bad connections. If bad connec-

tions are found, replace test leads.

5. Connect RED and BLACK test

leads across component where

you want to measure resistance.

When making resistance measure-

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