GMC 1977 motorhome Operating Manual page 94

HAZARD WARNING LIGHTS,
STOP LIGHTS (SFE-20)
SIDE MARKER LIGHTS, I .D . &
CLEARANCE LIGHTS, TAIL
LIGHTS DOME LIGHTS,
LICENSE LIGHTS (SFE-20)
CIGAR-CIGARETTE LIGHTER (SFE-20)
AUXILIARY BATTERY
SWITCH (AGC-5)
AIR SUSPENSION CONTROLS
30A CIRCUIT BREAKER
HEATER AND AIR CONDITIONER
CONTROLS (AGC-25)
CRUISE CONTROL, BACK-UP
LIGHTS (SFE-20)
TRANSMISSION CONTROL, PARKING
BRAKE LIGHT, GAUGES (AGC-10)
Headlight Beam Adjustment
NOTE: Cutouts in headlight bezel permit ac-
cess to adjustment screws.
Headlights should be adjusted properly. The
top adjusting screw provides vertical adjustment
and the side adjusting screw provides horizontal
adjustment. Headlights should not have to be
adjusted after replacing Sealed-Beam unit, pro-
viding headlights were in proper adjustment
before replacement and adjusting screws were
not disturbed during replacement .
Headlight Replacement
To replace a Sealed-Beam unit, remove bezel.
Then disengage the tension spring using a stiff
hooked tool. Rotate the Sealed-Beam assembly
slightly to disengage mounting ring slots from
groove of each adjusting screw, then pull for-
ward. Disconnect wiring at the base of unit and
separate the Sealed-Beam assembly by remov-
ing the two retaining screws. Install Sealed-
Beam unit in reverse order of removal .
EXTERIOR LIGHTS
All exterior lights can be easily replaced by
removing lens, pushing bulb in slightly and turn-
Chassis Fuse Block
8 8
ing counterclockwise, except side marker lights
which are simply pressed in. Then, with new
bulb, reverse procedure .
CHASSIS FUSES, FUSIBLE LINKS,
CIRCUIT BREAKERS
The wiring circuits in your vehicle are de-
signed to be protected from short circuits by a
combination of fuses, circuit breakers, and fusi-
ble thermal links in the wiring itself. This helps
to reduce the hazard of electrically-caused fires
in the vehicle .
The fuse and circuit breaker block is located
behind the glove compartment. To gain access to
the chassis fuse block, open the glove box door,
then release the secondary cable latch in the
back of the glove compartment. Glove box will
now come forward, exposing fuse block. All
chassis circuits are protected by fuses or circuit
breakers located here except :
HEATER BLOWER-Which has a fusible
link built into harness located behind the right
access door near the heater blower relay .
HEADLAMP CIRCUITS-Are protected by
a circuit breaker in the main light switch. An
electrical overload in the light circuit will