Fuse and Fusetron Replacement

TM 10-3930-609-12

(3) Remove the screws, flatwashers and

3-55. Thermal Relay

lockwashers securing the interlock switch to its

Each motor is protected by a thermal relay, ex-

bracket and remove the switch.

ternally mounted on the motor housing adjacent

b. Installation. Reverse the procedures in a

to the motor leads, which will open the motor

above.

circuit if overheating occurs. When temperature

sensed by the relay drops to a safe operating

3-51. Fuse and Fusetron Replacement

value, the relay will automatically close.

a. Removal.

(1) Remove fuse access cover (para 3-20).

(1) Remove screw, lockwasher and clamp

(2) Loosen screws (fig. 3-13) securing

which fastens relay to motor and lift relay from

fusetron to fuse panel and slide fusetron off fuse

motor.

panel.

(2) Scrap sealing compound from relay ter-

(3) Pull fuses straight off fuse panel.

minals. Unsolder leads at terminals.

b. Installation. Reverse applicable procedures

b. Installation. Reverse procedures in a above,

in a above to replace fusetrons and fuses.

soldering leads to terminals with rosin flux and

solder. Avoid unnecessary heating of the relay

3-52. Directional Control Switch

while soldering. Coat terminals after soldering

Maintenance of the directional control switch

with silicone rubber sealing compound.

(fig. 2-1) consists of replacing internal switches.

c. Test.

The switch need not be removed.

(1) Test electrical continuity of relay be-

a. Removal.

tween terminals with an ohmmeter or test light.

(1) Remove cover attaching screws and

Test at room temperature.

washers, or remove cover.

(2) If controlled temperature is available,

(1) Disconnect and tag leads from switch

test opening temperature of relay. It should open

terminals.

on rising temperature at 224oF, plus or minus

(3) Remove switch attaching screws and

4o.

nuts, and remove switch.

b. Installation. Reverse procedure in a above.

3-56. Accelerator Master Assembly

3-53. Pump Motor Switch

a. Removal.

(1) Remove floor plate from truck (para

(1) Remove valve cover (para 3-21).

3-18).

(2) Disconnect and tag leads at switch (fig.

(2) Disconnect linkage and spring from op-

3-17), loosen jamnut, and screw switch out of

erating lever (fig. 3-18), remove cover screws,

switch bracket.

and remove cover.

b. Installation. Reverse procedures in a above,

(3) Disconnect and carefully tag leads in-

turning switch in switch bracket to point where

side housing at switch terminal screws. Care-

switch is actuated when either the tilt or hoist

fully tag leads inside housing at switch terminal

lever is operated.

screws. Carefully draw leads out through conduit

fitting. Do not remove identification labels from

3-54. Seat Switch

leads.

a. Removal.

(4) Remove screws and lockwashers hold-

(1) Remove valve cover (para 3-21).

ing mounting bracket to truck and remove as-

(2) Disconnect and tag leads at switch (fig.

sembly.

3-17).

b. Repair. The following procedure does not

(3) Remove switch attaching screws, nuts

require removal of the assembly.

and lockwashers securing switch to bracket and

(1) Remove cover screws and cover.

remove switch.

(2) Disconnect leads at switch to be re-

b. Installation. Reverse procedures in a above,

placed, remove switch holddown screws, and re-

adjusting switch position up or down as required

move switch.

so that it is just actuated as the operator's seat

(3) Install new switch by reversing pro-

is fully lowered. Loosen bracket screws to posi-

cedures in (1) to (3) above.

tion bracket with attached switch for proper actu-

ation and then tighten bracket screws.

c. Installation. Reverse procedures in a above.

3-25