Pontiac FIREBIRD 1972 Service Manual page 1418

ACCESSORIES 15-3
CRUISE CONTROL DOES NOT DISENGAGE WHEN BRAKE IS APPLIED
CAUSE
Improper brake release switch adjustment.
Defective brake release switch.
Faulty valve body and magnet assembly.
CORRECTION
Adjust brake release switch.
Replace brake release switch.
Replace low speed switch.
CRUISE CONTROL RE-ENGAGES WHEN BRAKE IS RELEASED
CAUSE
Faulty engaging switch.
Terminal No. 1 grounded.
CORRECTION
Replace engaging switch.
Replace or repair wiring harness.
CARBURETOR DOES NOT RETURN TO NORMAL IDLE
CAUSE
Faulty Cruise Control linkage cable.
Improper accelerator linkage adjustment.
Weak or disconnected throttle return spring.
CORRECTION
Replace cable.
Adjust accelerator linkage.
Connect or replace spring.
PULSATING ACCELERATOR PEDAL
CAUSE
Speedometer cable or drive cable kinked.
CORRECTION
Replace cables if necessary.
CRUISE CONTROL DOES NOT CONTROL AT SELECTED SPEED
CAUSE
Faulty vacuum servo or vacuum hose.
Faulty governor assembly.
CORRECTION
Replace vacuum servo or vacuum hose.
Replace governor assembly.
CRUISE CONTROL CONTROLS SPEED 3 OR MORE M P H ABOVE SELECTED
SPEED
CAUSE
Improper centering spring adjustment.
CORRECTION
Adjust centering spring (C).
CRUISE CONTROL CONTROLS SPEED 3 OR MORE M P H BELOW SELECTED
SPEED
CAUSE
Improper centering spring adjustment.
CORRECTION
Adjust centering spring (C).