Dome Light; Compass And Radio Dial Lighting; Transistorized Light Dimming; Control Wheel Map Light - Cessna 177 SERIES Service Manual

ment panel lighting is controlled by a dimming rheo-
16-79. CONTROL WHEEL MAP LIGHT.
stat located on the left side of the instrument panel.
16-80. DESCRIPTION. An optional control wheel
16-70. REMOVAL AND INSTALLATION.
For re-
map light is available on the 177 model.
The map
moval and installation of instrument panel lights,
light is mounted on the underside of the control wheel
refer to figuer 16-9.
and the light intensity is controlled by a thumb oper-
ated rheostat. For dimming, the rheostat should be
16-71. DOME LIGHT. turned clockwise.
16-72. DESCRIPTION. The dome light is located in
the aft end of the overhead console and provides for CAUTION
cabin lighting. The dome light consists of a frosted
lens and a single bulb controlled by a switch located Thru 1970 aircraft only, failure to observe
in the center of the overhead console. polarity shown on wiring diagram (Section
20), .will result in immediate failure of the
16-73. REMOVAL AND INSTALLATION. For re- transistor on the map light circuit board
moval and installation of dome light, refer to figure assembly.
16-9.
16-81. REMOVAL AND INSTALLATION. (Thru
16-74. COMPASS AND RADIO DIAL LIGHTING.
1970 Aircraft Only) (See figure 16-11.)
a. For easy access to the map light assembly,
16-75. DESCRIPTION. The compass and radio dial rotate the control wheel 90'.
lights are contained within the individual units. The b. Remove the four screws from the map light cir-
compass light is controlled by the instrument light cult board.
The map light assembly will then be free
dimming rheostat and the radio lights are controlled for removal from the control wheel.
by the radio light dimming rheostat. Both rheostats c. Label the wires connecting to the map light cir-
are located on the left side of the panel, cuit board assembly and remove the screws securing
the wires to the circuit board assembly.
16-75A. TRANSISTORIZED LIGHT DIMMING. d. To install the map light assembly, reverse this
procedure.
16-75B. DESCRIPTION. Beginning with aircraft
serial 17702124 a remotely located two-circuit 16-82. REMOVAL AND INSTALLATION.
(BEGIN-
transistorized dimming assembly is installed to NING WITH 1971) (See figure 16-11).
control aircraft lighting. One circuit controls the a. For easy access to the map light assembly ro-
eyebrow lights, compass light and console light,
-tate the control wheel 90
° .
also post lighting if installed. The other circuit b. Beginning with 1972 Models, remove terminal
controls engine instrument and radio lighting. The block cover.
dimming assembly is located on the inboard side of
c. Label the wires connecting the map light assem-
the glove box. Two dimming rheostats on the pilots
bly (terminal block) and remove screws securing the
switch panel control power through the dimming
wires to the terminal block.
assembly. One rheostat is for panel lighting and the d. Remove screws securing map light to the control
other for engine instrument and radio lighting,
wheel and remove map light assembly.
e. For reassembly reverse this procedure.
16-75C. REMOVAL AND INSTALLATION. For re-
moval and installation of the dimming assembly refer
16-83. PITOT HEATER.
to figure 16-10A.
16-84. DESCRIPTION. An electrical heater unit is
16-76. COURTESY LIGHTING.
installed in some pitot tubes. The heater offsets the
possibility of ice formation on the pitot tube. The
16-77. DESCRIPTION. A courtesy light is located
heater is integrally mounted in the pitot tube and is
on the underside of each wing and in the lower por- controlled by the pitot heat switch.
'See figure 16-12.)
tion of the pedestal. The switch operating all three
For Trouble Shooting refer to Section 15.
courtesy lights is located on the left hand doorpost.
16-78. REMOVAL AND INSTALLATION. For re-
moval and installation of courtesy lights, refer to
figure 16-10.
Change 6
16-27