Pontiac FIREBIRD 1972 Service Manual page 1425

15-10 1972 PONTIAC SERVICE MANUAL
OVERRIDE
The accelerator pedal may be depressed at any time to
override the cruise system. Release of the accelerator
pedal will return the car to previous cruise speed.
MAJOR COMPONENTS
The major components of the cruise control system are:
pushbutton engaging switch
regulator assembly
vacuum servo
OPERATION
ELECTRICAL CIRCUIT (Fig. 15-7)
Battery current is supplied to contact C in the engagement
switch through the underdash accessory power circuit. A
release switch is inserted in this circuit to break the con-
nection whenever the brake pedal is depressed.
When the engagement button in the turn signal lever (Fig.
15-8) is depressed to the engage position, a circuit is made
between contacts A & B, and the power source
-
contact
C. Current will now be supplied to the regulator assembly
at both terminals 1 & 2.
Current passes from terminal 1 (black wire) through the
winding in the solenoid valve to ground. A low speed
switch is inserted in this circuit to break contact at low
release switches (electric and vacuum)
speeds (below approx. 30 mph).
CRUISE
[ENGAGEMENT SWITCH
I
SERVO VACUUM
SOURCE
Fig. 15-7 Cruise Control Circuit Diagram
SWITCH SEQUENCE CHART
BUTTON POSITION
, C R ~ (NORMAL)
ENGAGE (DEPRESSED MIDWAY)
.TRIM (DEPRESSED FULLY)
m r r c r
c
TO
A
I c m c r
c
TO
B
I
CONTICT
A TO
E
CLOSED
1
OPEN
I
OPEN
CLOSED ]CLOSED
1
CLOSED
OPEN l W E N
CLOSED