Cruise Control: Description and Operation

When the ignition switch is in the ON or START position, power is supplied
^ through 7.5 A fuse (No. (1), located in the fuse block)
^ to Automatic Speed Control Device (ASCD) hold relay terminal (5) and
^ to ASCD main switch terminal (1)
When ASCD main switch is in the ON position, power is supplied
^ from ASCD main switch terminal (3)
^ to ASCD hold relay terminal (1).
Ground is supplied
^ to ASCD hold relay terminal (2)
^ through body grounds (M5) and (M57).
With power and ground supplied, the ASCD hold relay is energized, and power is supplied
^ from ASCD main switch terminal (3)
^ to ASCD control unit terminal (4) and
^ to ASCD main switch terminal (2).
After the ASCD main switch is released, power remains supplied
^ to the coil circuit of ASCD hold relay
^ through ASCD main switch terminals (2) and (3)
This power supply is kept until one of following conditions exists.
^ Ignition switch is returned to the ACC or OFF position.
^ ASCD main switch is turned to OFF position.
During ASCD hold relay is energized power is also supplied to ASCD control unit terminal (5)
^ through ASCD clutch switch and ASCD brake switch (M/T models) or
^ through ASCD brake switch, ASCD hold relay and park/neutral position relay (A/T models).

Inputs
At this point, the system is ready to activate or deactivate, based on inputs from the following:
^ speedometer in the combination meter
^ stop lamp switch
^ ASCD steering switch
^ park/neutral position relay (A/T models)
^ ASCD clutch switch (M/T models)
^ ASCD brake switch.
A vehicle speed input is supplied
^ to ASCD control unit terminal (7)
^ from terminal (18) of the combination meter.
Power is supplied at all times
^ to stop lamp switch terminal (1)
^ through 10 A fuse (No. (7), located in the fuse block).
When the brake pedal is depressed, power is supplied
^ from terminal (2) of the stop lamp switch
^ to ASCD control unit terminal (11).
Power is supplied at all times
^ through 10 A fuse (No. (38), located in the fuse and fusible link box)
^ to horn relay terminal (2)
^ through terminal (1) of the horn relay
^ to ASCD steering switch terminal (21).
When the SET/COAST switch is depressed, power is supplied
^ from terminal (22) of the ASCD steering switch
^ to ASCD control unit terminal (2).
When the RESUME/ACCEL switch is depressed, power is supplied
^ from terminal (23) of the ASCD steering switch
^ to ASCD control unit terminal (1).
When the CANCEL switch is depressed, power is supplied to ASCD control unit terminals (1) and (2).
When the system is activated, power is supplied to ASCD control unit terminal (5).
Power is interrupted when
^ the shift lever is placed in P or N (A/T models)
^ the clutch pedal is depressed (M/T models) or
^ the brake pedal is depressed.

Outputs
The ASCD actuator controls the throttle drum via the ASCD wire based on inputs from the ASCD control unit.
The ASCD pump consists of a vacuum motor, an air valve, and a release valve.
Power is supplied
^ from terminal (8) of the ASCD control unit
^ to ASCD pump terminal (1).
Ground is supplied to the vacuum motor
^ from terminal (9) of the ASCD control unit
^ to ASCD pump terminal (4)
Ground is supplied to the air valve
^ from terminal (10) of the ASCD control unit
^ to ASCD pump terminal (2).
Ground is supplied to the release valve
^ from terminal (14) of the ASCD control unit
^ to ASCD pump terminal (3)
When the system is activated, power is supplied
^ from terminal (13) of the ASCD control unit
^ to combination meter terminal Oil and
^ to A/T control unit terminal (37) (A/T models).
Ground is supplied
^ to combination meter terminal (22)
^ through body grounds (M5) and (M57).
With power and ground supplied, the CRUISE indicator illuminates.
When vehicle speed is approximately 8 kph (5 mph) below set speed on A/T models, a signal is sent
^ from terminal (12) of the ASCD control unit
^ to TCM (transmission control module) terminal (40).
When this occurs, the TCM (transmission control module) cancels overdrive.
After vehicle speed is approximately 3 kph (2 mph) above set speed, overdrive is reactivated.