The Control Module is located behind the
instrument panel on the right hand side, behind the wiring harnesses.
The fuse in the
control box needs to be checked for wirings of the horn getting short. Also if
the horn fuse is blowing again n again then replace the horn fuse with but high
ampere fuse then check.
The Vehicle
Speed Sensor (VSS) is mounted to the transmission and provides a low voltage
Alternating Current (AC) signal to the Cruise Control Module (CCM). The CCM
converts the AC signal to a pulse width modulated Direct Current (DC) signal,
which is sent to the cruise control module at a rate of 4000 pulses per mile.
Cruise Control Module:
The cruise control module has to do three things. First it remembers the speed
you set. It stores this set speed until you change it or turn off the ignition.
Next it takes the speed signal from the vehicle speed sensor and compares it to
the set speed. Lastly it sends pulse signals to the actuator. The actuator will
move the throttle linkage to bring the vehicle up to the set speed and then
modulate vacuum to maintain that speed.
Actuator:
The actuator is what actually moves the throttle linkage. It is most often
vacuum operated although some actuators are electrically controlled with small,
stepper type motors. The actuator moves the linkage as directed by the cruise
control module until the set speed has been achieved. It then maintains this
speed by controlling the amount of vacuum. It actually modulates the vacuum as
the pulses from the control module direct.
Brake Switch:
The cruise control release switch and stop lamp switch are used to disengage
the cruise control system. A cruise control release switch and a stop lamp
switch, mounted on the brake pedal bracket disengage the system electrically
when the brake pedal is pressed. This is accomplished by interrupting the flow
of current to the cruise control module. The cruise speed of the vehicle at
brake actuation will be stored in the cruise control module memory.
Throttle Linkage:
The actual mechanical connection between the cruise control actuator and the
engine throttle.
Now that was the detail about cruise control.
But if the control is turning on then going off in few seconds or minutes then
is problem and there are few possibilities:--
If
the vehicle speed sensor fails, the cruise control module will not get a speed
signal. If this is the case the speedometer will usually stop working as well.
The cruise control module can go bad and either not understand the signal
coming in from the vehicle speed sensor or is unable to send the signal to the
actuator. In addition blown fuses or broken wires can prevent the cruise
control module from working properly as well. The vacuum diaphragm
inside the actuator can develop a leak and prevent it from operating properly.
If it is a large vacuum leak the actuator will probably not set at all. Leaking
or broken vacuum lines are usually the major cause of this
problem. Lastly, the linkage itself may break or become
disconnected. Some cruise control systems use a bead type chain, like the pull
chain on an old light socket, and they just plain break.
Thanks. Keep updated for any more
query. You can rate this solution and show your appreciation.
Thank you kapishteck, the location and break-down will be very helpful. I might just add that the dash light that tells me that the speed control is on, goes out when the speed control stops working going down the road. At first, the light would go out(and of course the controler would disengage) I would wait just a little while (sometimes right away and sometimes minutes or hours) then push the on button on the steering wheel and it would come back on. It would not keep the the speed in the memory, it was like I turned it off my self. If I thouched the horn it would blow a fuse. Finally it quit working altogether.
I just came in for lunch and haven't had a chance to do anything yet. But I thought I would add this info. After reading your reply, it sounds like I have a bad power supply to the control module.
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