TM 5-2410-240-23-3
0283
ELECTRICAL CONNECTORS AND WIRING INSPECTION CONTINUED
6. If at least one intermittent fault was indicated:
a. Perform open circuit test on suspect harness and replace affected harness.
b. Use electronic technician (ET) to clear logged diagnostic codes and verify that repair eliminated the fault.
END OF TASK
WIRING HARNESS OPEN CIRCUIT TEST
000283
An open is a failure of any electrical circuit that results in no flow of electrical current. An open circuit is usually
caused by failed electrical wires or a poor connection. If an electrical wire or a connection is broken, flow of
electrical current through the circuit is interrupted. A normal closed circuit will have less than 5 ohms of resistance.
Test Procedure
000283
1. Identify connectors and wire numbers of suspect circuits. Use electrical schematic of machine to identify
circuits (WP 0286).
2. Turn ignition switch and battery disconnect switch to OFF position.
3. Isolate wiring harness by disconnecting suspect component connector from component and ECM connector
from ECM.
4. At suspect connector end of disconnected wiring harness, place a jumper wire from contact of suspect wire to
frame ground.
5. At ECM end of wiring harness, use multimeter probes to measure resistance from contact of suspect wire to
frame ground.
a. If resistance between suspect wire of disconnected connector and frame ground is less than 5 ohms,
harness circuit is OK.
b. If resistance between suspect wire of disconnected connector and frame ground is 5 ohms or greater,
there is an open in harness of suspect wire. Replace harness.
END OF TASK
WIRING HARNESS SHORT CIRCUIT TEST
000283
A short circuit is a failure of an electrical circuit that results in undesired electrical current. Usually, a short circuit is
a bypass of circuit across a load. For example, a short across wires in a circuit for a lamp produces too much
current in the wires, but no current is felt at lamp. Lamp is shorted out. Resistance in a normal circuit can vary, but
resistance between a particular circuit and other unrelated circuits is always greater than 10,000 ohms.
Test Procedure
000283
1. Identify connectors and wire numbers of suspect circuits. Use electrical schematic of machine to identify
circuits (WP 0286).
2. Turn ignition switch and battery disconnect switch to OFF position.
3. Isolate wiring harness by disconnecting each end of suspect circuit from component and in-line harness
connector or ECM connector from ECM.
4. At ECM or in-line harness connector end of wiring harness, place one multimeter probe on contact of suspect
wire.
0283-4
