opening in housing. Install outer nuts and insert
ends of wire core into mechanical posts of damper
and actuator. Tighten outer nuts on casing.
(2) Install clamp, spacer, screw, nut, and
(3) Refer to paragraph 4-27 and adjust the
( 4 ) R e f e r t o p a r a g r a p h 4 - 2 1 a n d i n s t a ll
( 5 ) R e f e r t o p a r a g r a p h 4 - 1 8 a n d i n s t a ll
evaporator inlet and outlet louvers.
MAINTENANCE OF ELECTRICAL SYSTEM
The electrical system consists of the evaporator and
condenser fan motors, electric heaters and heater
thermostatic switch, junction box, control module,
transformer, rectifier, condenser fan motor, high-
low speed thermostatic switch and connecting
harnesses and wiring. Single phase air conditioners
are equipped with motor capacitors and a com-
pressor start relay. Three phase air conditioners are
equipped with phase sequence relays. Electrical
assemblies and groups of associated components
are covered in separate sections.
Warning: Disconnect air conditioner power
s u p p l y b e f o r e p e r f o r m i n g m a i n t e n a n c e w o rk
on electrical system.
4-32. Testing and Inspecting the Electrical
Troubleshooting procedures for testing the elec-
trical system to isolate cause of trouble are covered
in paragraph 4-12. Additional detailed test in-
formation is contained in
covering the electrical components. Use a con-
tinuity tester or multimeter set on low ohms range
to test for continuity. Use an insulation tester or
multimeter set on higher ohm range to test for
shorts between the circuit in a component and the
outside case of the component. When testing air
electrical component, check also for visual damage
and inspect all wiring in the area for damage or
4-33. Wiring Harnesses and Leads
a. G e n e r a l . The electrical circuits in the air
conditioner are completed by individual wire leads
or by wire leads laced or enclosed in a loom to form
a wiring harness. All of the wiring carries code
numbers. When testing, repairing or replacing the
wiring harness or individual wires, refer to the
b. Inspection. Inspect all wiring installation for
cracked or frayed insulation material. Pay par-
ticular attention to wires passing through holes in
the frame or around sharp edges. Repair or replace
defective wiring. Inspect electrical connectors and
fittings for damage or broken condition. Replace
defective connectors and fittings.
c. Testing. Test for continuity in leads or wiring
harnesses by disconnecting each end. Where wires
terminate in an electrical connector, disconnect
connector from corresponding receptacle connector
or plug connector. Touch the test probes of a
continuity tester or multimeter set on low ohms
range to ends of wire or corresponding pin of
connector. If continuity is not indicated, repair or
d. Repair. Remove insulation to expose 1/2 inch
of bare wire on each side of break. Twist the wire
ends together and solder the splice. Cover the splice
with rubber or PVC electrical tape and friction tape
making certain to cover all the repaired area.
Replace broken terminal lugs with exact duplicates.
To replace electrical connectors, unsolder wires
from solder wells
and insert ends of
in place. Check
to inserts. Install new connector
wires in solder wells. Solder wires
connections carefully. Refer to
MAINTENANCE OF HEATERS AND THERMOSTATIC SWITCH
4-34. Heater Thermostatic Switch
(1) R e f e r t o p a r a g r a p h 4 - 2 1 a n d r e m o ve
a. General. The heater thermostatic switch
housing front cover.
mounted in a bracket under the housing center
(2) Refer to figure 4-9 and remove two screws
cover, protects the air conditioner from overheating
(1) to remove bracket and switch from center cover.
if the heating element circuit is actuated and the air
(3) Remove two screws (2) and lock washers
flow is restricted or stopped.
(3) and remove bracket (4).
b. Removal. Remove the switch as follows:
(4) Remove switch screws (5) and disconnect
leads (6) from thermostatic switch (7).