RELAY INSPECTION AND TESTING

TM 9-2320-312-24-1

ELECTRICAL GENERAL MAINTENANCE INSTRUCTIONS - CONTINUED

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RELAY INSPECTION AND TESTING - CONTINUED

NOTE

When testing a relay, refer to the circuit diagram on relay case.

Using a multimeter, test for continuity across relay coil. Coil should have continuity. If not, replace relay.

Using a multimeter, test for closed contacts within relay. Contacts should be open (no continuity). If contacts are stuck

closed, replace relay.

CIRCUIT BREAKER INSPECTION AND TESTING

NOTE

Circuit breakers may be inspected and tested while installed in vehicle.

Inspect circuit breaker for damaged or corroded terminals.

Inspect circuit breaker for burned or damaged housing or reset button.

If any of these conditions are evident, replace circuit breaker. If none of these conditions are evident, test circuit breaker.

(Refer to step 4)

With reset button in the fully outward position, depress reset button to "reset" circuit breaker. Reset button should

remain depressed. If not, circuit breaker is defective or an electrical problem exists in another part of the electrical cir-

cuit.

Isolate circuit breaker by disconnecting one wire from rear of circuit breaker. Again depress reset button. If reset button

does not remain depressed, replace circuit breaker.

WIRING HARNESS REPLACEMENT

NOTE

Wiring harnesses are composed of multiple wires enclosed in a protective wire loom with one or more

connectors of varying configurations at each end. When damaged, wiring harnesses can be repaired by

replacing connectors or by splicing wires. If damage is extensive, entire wiring harness should be

replaced.

Perform the following steps to replace a typical wiring harness. Refer to electrical schematics in fold-

outs at back of manual for assistance.

Tag wire leads and connectors to ensure correct installation.

Provide access to wiring harness, as necessary, by removing instrument panel, tilting cab, raising fifth wheel, removing

rear platform etc.

Place battery disconnect switch in OFF position.

Remove mounting hardware (nut, locknut, lockwasher, screw etc.) or disconnect connector(s) of wiring harness to dis-

connect wiring harness from electrical component at one end of wiring harness.

Trace length of wiring harness and remove tiedown straps and clamps, as necessary. Discard tiedown straps.

Repeat step 3 at other end of wiring harness.

Remove wiring harness from vehicle.

NOTE

Ensure wire loom is installed over wiring harness as required prior to installation.

Position wiring harness to vehicle.

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