TM-9-2320-273-20

TRUCK TRACTOR, LINE HAUL; LIGHT EQUIPMENT TRANSPORTER; TRUCK CHASSIS; MEDIUM EQUIPMENT TRANSPORTER

TECHNICAL MANUAL; ORGANIZATIONAL MAINTENANCE

NOVEMBER 1980

TM-9-2320-273-20 - Page 425 of 1500

TM 9-2320-273-20

5-6. TEST EQUIPMENT (Continued).

d. Testing for Shorts.

A short (or short circuit) occurs when two circuits that should not be con-

nected have metal-to-metal contact with each other. A short also occurs when a circuit that should not

touch ground has metal-to-metal contact with ground. To check for shorts, do the following steps:

Failure to do the following step can damage the multimeter.

(1)

Disconnect the circuit being tested. T

O

be safe, disconnect the battery ground cable.

(2)

Set

UP

and “zero” the multimeter (para b.).

(3)

Wiith any of the three multimeters, connect one probe to one circuit and the other

probe to the other circuit or ground (if checking for a short to ground). Figure 5-6 shows a check

to see if wire “A” is shorted to wire “B” in the wiring harness.

Figure 5-6. Testing for Shorts

(4)

Look at the needle.

(a)

If the needle swings to the far right over the

“O”

on the top scale (on all three

multi meters), the circuits are shorted.

(b)

If the needle doesn’t move

r

the circuits are not shorted.

(c)

If needle jumps or flickers, the circuits are occasionally shorted.

e. Testing Resistance.

To measure resistance in a circuit do the following steps.

Failure to do the following step can damage the multimeter.

TA 074695

5-9