Cruise Control Sometimes my cruise control will come on and sometimes it will not

Impossible to answer because .........

NO 'year make model'.

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year make model cruise control not working

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Which engine ?
Cruise Control Description and Operation (3.6L)
Cruise Control Description and Operation (3.4L)

Do you know what all is involved in C.C. operation ?


Cruise control is a speed control system that maintains a desired vehicle speed under normal driving conditions at speeds above 40km/h (25 mph). However, steep grades may cause variations in the selected speeds. The main components of the cruise control system are:
• The cruise control module assembly
• The cruise control switches
• The cruise control release switch
• The powertrain control module (PCM)
• The stoplamp switch assembly
• The vehicle speed sensor


The cruise control module controls the operation of the cruise control system. The cruise control module monitors the signal circuits of the cruise control switches. When the normally open cruise On/Off switch closes with a switch activation, the cruise control modules detects a high voltage on the signal circuit. The cruise control module activates the cruise control system.The set/coast switch and the resume/accel switch will not operate the system when the cruise control module has not activated the system based on the cruise control on/off switch signal circuit .
The cruise control module monitors the cruise control set/coast switch in order to determine when to capture and maintain the vehicle speed. The cruise control module monitors the vehicle speed signal circuit in order to determine the desired speed. The PCM pulses the vehicle speed signal circuit at 4000 pulses per minute. After an initial set speed has been established, the cruise control module also uses the cruise control set/coast switch signal circuit in order to tap down the set speed when the cruise control module detects a switch activation.
The cruise control module monitors the cruise control resume/accel switch signal circuit in order to determine when to resume the previous set speed. This feature only works within the same ignition cycle and as long as the cruise wasn't turned off using the cruise control On/Off switch since the last cruise engagement. After the set speed has been resumed, the cruise control module also uses the cruise control resume/accel switch signal circuit in order to tap up the set speed when the cruise control module detects a switch activation.
The cruise control module assembly has a controller and an electric stepper motor to vary the throttle in each different cruise control mode. Two components in the module assembly help to do this. The electronic controller and the electric stepper motor. The controller monitors vehicle speed and operates the stepper motor. The stepper motor operates in response to the controller, to maintain the desired cruise speed. The electric stepper motor moves a strap that is attached to the cruise control cable which moves the throttle

Sounds like the multifunction switch has failed.

not being informed if it is auto or manual, here are some of the items that control the cruise control
brake pedal sensor ,
clutch pedal sensor,
vehicle speed sensor
engine ignition control module , tacho ,
vehicle speed --will disconnect if the road speed is below setting minimum speed
ratio changing
bad cruise control switch
wiring and connections
ecm problems
problem cruise control module

could be speed sensor.

are you going uphill in overdrive gear . If the speed is lower than you set the crruise control might disengage. ?

Hi, This needs a new cruise control switch fitting not a job for the faint hearted there are a lot of wires that need to be connected properly, recommend any good vehicle electrics company or cruise control specialist is best. Please give feedback at [email protected] Thanks, Malcolm Campbell.

I have a 2004 Mercury Mountaineer AWD Premier V6 4.0L and the fix was simple for me. My problem was the cruise control working off and on randomly. Part number SW-6349 3L3Z-9F924-AB. I put this on myself and it worked like a charm.

sounds like a vacuum problem

When my 1999 Cabrio was new the cruise control went out. It took the dealership and along with a VW expert 10 days to find a pinched harness assembly under the battery box.