Chevrolet 10 Series 1968, Service Manual

Page: 676 / 713

ACCESSORIES 15-2
which is linked to a speedometer-like mechanism. The
speedometer cable from the transmission drives the
Regulator, and a cable from the Regulator drives the
instrument panel speedometer. The engagement of the
Regulator unit is controlled by an Engagement Switch
located at the end of the turn signal lever. Brake and
clutch release switches are provided: Electric switches
which disengage the Regulator unit.
The operation of each unit of the system and the
operation of the entire system under various circum­
stances is described below. Figure 1 shows the location
of the system components within the vehicle.
COMPONENT OPERATION
ENGAGEMENT SWITCH
This switch, located within the turn signal knob, has
three positions. In the fully released position, the switch
passes current through resistance wire to effect a "hold
in” magnetic field in the Regulator solenoid. This cur­
rent is sufficient only to hold the solenoid in place once
it has been actuated by the ' ‘pull in " circuit. Depressing
the button partially allows current to flow to the Regu­
lator solenoid at full voltage which causes the solenoid
to pull in. Depressing the button fully opens the circuit
to both the resistance and standard solenoid feed wires
and the solenoid becomes de-activated.
During vehicle operation the three switch positions
have the following functions:
Released
a. System not engaged: No function of the system
will occur although a small current is flowing
through the solenoid via the resistance wire (at
vehicle speeds over 20 mph).
b. System engaged: The small current flowing
through the resistance wire is holding the sole­
noid in the engaged position.
The regulator unit is controlled by an Engagement Switch
located at the end of the turn signal lever. Brake and
clutch release switches are provided: Electric switches
disengage the Regulator unit.
The operation of each unit of the system and the op­
eration of the entire system under various circumstances
is described below. Figure 1 shows the location of the
system components within the vehicle.
Partially Depressed
Fully voltage is applied to the solenoid (vehicle speed
over 20 mph) which sets the Regulator to maintain the
vehicle speed at the time of Regulator engagement.
Fully Depressed
No electricity flows to the solenoid and the Regulator
is inactive. This position is used by the driver when he
desires to raise or lower his controlled speed. He may
accelerate to his new speed, press the button fully (Regu­
lator releases previously set speed) and release the but­
ton. Upon releasing the button, it passes through the
partially depressed position and the solenoid is “ pulled
in” , then into released position which provides “ hold in”
current. The driver may also press the button fully with
no pressure on the accelerator pedal. In this case the
regulator releases control of the throttle which returns
to idle and the car slows. When the button is released
the solenoid is pulled in and held in respectively and the
regulator resumes speed control at the speed of the
vehicle during the moment of button release (at vehicle
speeds over 20 mph).
BRAKE RELEASE SWITCHES
Two brake release switches are in the Cruise Master
System. When the brake pedal is depressed, an Electric
Release Switch cuts off the voltage supplied to the en­
gagement switch, hence cuts off power to the Regulator
unit. The Regulator is then disengaged and requires
Engagement Switch operation to return it to operation.
F ig . 2 —Cru ise Master Engagement Sw itch F ig . 3 —Regulator Unit
AIR FILTER AND —^
SOLENOID HOUSING COVER
LOCK NUT
ORIFICE TUBE
AND CONNECTOR
ASSEMBLY
CHEVROLET TRUCK SERVICE MANUAL