Wiring

TM 10-3930-630-12

4-49.

Wiring

electrical tape if possible.

a. General. Electrical wiring for the truck

(3) Replace

damaged

wires

and

terminals.

consists mainly of two harnesses. A harness with a

(4) Tighten clamp mounting screws and

multiple plug connects the instruments and fuses on the

install missing clamps if necessary.

instrument panel Connection to the frame harness is

made with a matching multiple plug at the right side of

4-50.

Sending Units

the instrument panel Additional wires connect to the

horn, transmission neutral start switch, fuel level gage

a. General. The engine oil pressure gage,

and transmitter, and between instruments on the panel

The engine ignition and associated wiring are covered in

hourmeter, coolant temperature gage, and fuel level

their appropriate paragraphs.

gage are actuated by sending units mounted on the

b. Inspection.

engine and fuel tank. Connections are made to the oil

and temperature gages through the frame wiring

CAUTION

harness. Two wires connected by a quick-disconnect

coupling lead from the fuel tank to the fuel gage. The

fuel level gage sending unit is covered with the fuel

Before attempting any replacement or

tank.

repairs to the electrical system, refer to

b. Oil Pressure Gage Sending Unit. The oil

paragraph 446 and disconnect the battery

pressure and hourmeter actuator sending units are

ground (negative) cable.

mounted on the engine crankcase on the left side below

(1) Check electrical connections for

the air cleaner.

security.

(1) Inspection. Open left side panel to

(2) Inspect wires for damage to insulation,

wire and terminals.

gain access to the oil pressure gage sending unit.

(3) Check clamp for secure mounting.

(a) Check wire connections to

c. Repair.

sending units

(1) Tighten

loose

connections

necessary.

(2) Cover damaged insulation with

Figure 4-33. Oil pressure and hourmeter actuator sending units, installed view.

4-43