Cessna 177 SERIES Service Manual

15-42.
TROUBLE
SHOOTING
(Cont).
TROUBLE
PROBABLE
CAUSE
REMEDY
CONTROL
WHEEL
MAP
Nav
light
switch
turned
off.
1. Nav
light
switch
has
to be
ON
LIGHT
WILL
NOT
LIGHT
before
map
light
will
light.
THRU
1970
AIRCRAFT
ONLY.
Short
circuit
in wiring.
2.
Check
lamp
fuse
on
terminal
board
located
on
back
of
stationary
panel
with
ohmmeter.
If fuse
is
open,
proceed
to step
3. If
fuse is
OK,
proceed
to step
4.
Defective
wiring.
3.
Test
circuit
until
short
is lo-
cated.
Repair
or replace
wiring.
4.
Test
for
open
circuit.
Repair
or replace
wiring.
If a
short
or
open
circuit
is not found,
proceed
to step
5.
Defective
map
light
assembly.
5.
Check
voltage
at
map
light
assembly
with
master
and
nav
switches on.
If battery voltage
is
present, replace
map light
assembly.
CAUTION
Failure
to observe
polarity
shown
on wiring
diagrams
11. 7.
0,
will
result
in immediate
failure
of the
transistor
on the
map
light
circuit
board
assembly.
CONTROL
WHEEL
MAP
Nav
light
switch
turned
off.
1.
Nav
light
switch
has
to
be
LIGHT
WILL
NOT
LIGHT
ON
before
map
light
will
light.
1971
AIRCRAFT
&
ON.
Short
circuit
in wiring.
2.
Check
lamp
fuse
on
terminal
board
located
on
back
of station-
ary
panel
with
ohmmeter.
If
fuse is
open,
proceed
to step
3.
If
fuse
is OK,
proceed
to
step
4.
Defective
wiring.
3.
Test
circuit
until
short
is lo-
cated.
Repair
or replace
wiring.
4.
Test for
open
circuit.
Repair
or
replace
wiring.
If
a short
or
open
circuit
is not
found,
proceed
to
step
5.
Defective
map
light
assembly.
5.
Check
voltage
at
map
light
assembly
with
master
and
nav
switches
on.
If
battery
voltage
is present,
replace
map
light
assembly.
16-18 Change 4

Cessna 177 SERIES Specifications

General

Manufacturer	Cessna
Engine Type	Piston
Wingspan	35 ft 6 in (10.82 m)
Seating Capacity	4
Number Built	4, 295
Engine	Lycoming O-360
Horsepower	180 hp
Maximum Takeoff Weight	2, 500 lb (1, 134 kg)