Wiring Harness and Wire Leads.

TM 5-4120-355-14

5-10. Wiring Harness and Wire Leads.

a. General. The electrical circuits in the refrigeration unit are completed by individual wire leads or by leads laced ---

or enclosed to form a wiring harness. When testing, repairing, or replacing the individual wires or harnesses, refer to wir-

ing diagram, figure 1-3.

b. Inspection. Inspect the wiring insulation for cracks and frayed material. Pay particular attention to the wires

passing through holes in the frame or over rough edges. If inspection revealsa broken or cut wire, and the break in the

wire is exposed, the wire must be repaired (d below). If thebreak ina wire is ina harness or inaccessible area replace wire

(e below).

c. Testing. Test a wire for continuity by disconnecting each end from the component to which it is connected.

Touch the test probes of a multimeter to each end of the wire. If continuity is not indicated, the wire is defective and

must be repaired or replaced.

d. Repair. Remove the insulation on the wire to expose one-half inch of bare wire at both ends of the break. Twist

bare wire together and solder the connection. Cover the repaired break with electrical tape and friction tape. Do not leave

any bare wire exposed. If a terminal lug breaks off a wire, replace it, using an exact duplicate terminal lug.

e. Replacement. Replace a wire by disconnecting it from the component and remove the wire. Install a new wire

and connect it to the component. If a broken wire is part of a wiring harness, disconnect the wire at each end and tape

these ends with electrical tape. Install a new wire and attach it to the outside of the wiring harness.

511. Tubing and Fittings

The refrigerant piping used on the air conditioning units consists of copper tubing and necessary fittings. Joints of

refrigeration pipes and fittings are soldered. Inspect the piping and fittings for cracks and breaks (para 4-40). Replace de-

fective pipes with those of the same length, size, shape, and material. When soldering or unsoldering items such as the

thermostatic expansion valves, or solenoid valves, disassemble valves and wrap valves bodies with a damp cloth to protect

them from damage by heat.

Section IV. Removal and Installation

512. Compressor

The sole purpose of the compressor is to raise the pressure of refrigerant gas from evaporator pressure to condensing

pressure. The function of the compressor is to deliver refrigerant to the condenser at a pressure and temperature at which

the condensing process can readily be accomplished. The motor/compressor is a hermetically sealed unit and is not re-

pairable in the field. An inoperative compressor is usually due to a mechanical failure causing the compressor to freeze,

control failure, or a motor burnout. If the motor/compressor is mechanically frozen or there has been a motor burnout,

the compressor must be removed and replaced. When the motor of a hermetic compressor fails, high temperatures may

develop within the compressor causing a breakdown of the oil and refrigerant, resulting in a formation of acid, moisture,

and sludge. All these are extremely corrosive and must be flushed from the system. Repeated burnouts will occur if all

of the contaminants are not removed.

5-13. Removal and Installation of Compressor.

a. RemovaL

(1) Remove front access panel (para 4-15) and pullout junction box and control box (para 4-24 and 4-28).

(2) Discharge refrigerant from system (para 5-9b).

(3) Refer to figure 4-7 and remove compressor through front of unit.

5-6