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I can't seem to get my cruise to stay "on" Sometimes it won't even set....and when it does it may stay on for 2 min or 5 min and then off.........why......I need help thanks all............Jb
 

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Well mine doesn't work because all of the computer stuff has been disconnected I want to get one of the aftermarket types and put on I just don't know about the turn signal with the delay wipers and it having stock cruise control.
 

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The cruise is totally independent of the computer system and will function without the ECM.
 

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no it wont it uses the input from the speed sensor to control it. i disconnected the computer stuff on my 84 camaro and the cruise stopped working, all components check good just no function. check your brake switch for the cruise (the one with the hose on it) the one on my elco is going bad and the cruise comes and goes
 

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I concur with CCC on the ECM requiring input from from the speed sensor to manage the cruise control.

I must say however I have never caught acauth1 in an error. Maybe this is his first. I'm sure he'll let us know.

Doug
 

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the early elcos with the transducer mounted on the fenderwell with speedo cables to and from it will work stand alone but an 85 has the vacuum /electric unit that mounts above the driverside valve cover needs the ecm .when i had a holley on my 86 the cruse wouldnt work either,put the q jet back on to get the cruise working again. the 95 lt1 ecm i am going to put in my 86 has a wire from the ecm labled cruise enable. but back to the original part of this thread check your vacuum lines and check valve to your cruise unit .check the ground wire from the unit to its mounting bracket.check your brake disable switch,check the small flat connector comeing from the steering column.make sure its clean and well connected. it alls good may be a bad switch or control unit.the control unit mounts on a bracket above the gas pedal
 

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I will be the first to admit I can be wrong, just ask my wife!

However, in this instance, I am correct.

I answered the original poster with a link to an article I wrote several years ago describing the operation and diagnosis of the 84-87 Custom Cruise III System, which is the system on his car. Everything needed to correctly troubeshoot the cruise system is there.

The ECM has no control whatsoever over the cruise system since the cruise has its own control module (CCM), independent of the ECM.

The ECM does receive a signal from the V.S.S, (vehicle speed sensor) and uses that signal to monitor vehicle speed, and control the lockup converter, not the cruise control.

The ECM does not know, or even care for that matter, if the cruise is engaged or not, there is no input from the cruise to the ECM.

Granted, on many later model vehicles, the ECM/PCM does control the cruise, yet the 84-87 cruise III system does not.

I have worked with the GM Cruise III system since it first came out, its predecessors well before and many different systems since.
I have also removed many ECM's from my personal and customer 84-87 G-Bodies without affecting cruise operation.

And again, for those who wish to learn how this system works and how to troubleshoot it:
http://www.elcaminocentral.com/showthread.php?t=27191
 

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I need to get information on how to contact acauth1's wife. There has to be something to rag him about on his erroneous ways.

Well I learned a little about how the cruise control is managed. Did not know there was such a thing as a CCM module. Think I'll have to take a look in my shop manuals.

EDIT: The link in acauth1's post is better than the shop manual.

http://www.elcaminocentral.com/showthread.php?t=27191

Doug
 

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not trying to prove anyone wrong here we are all here to see the same result.i was just stating from personal experiance if there is a unseen connection i am missing i would apreciate you pointing it out to me.i just stated that mine quit working without the computer functioning .and all that was disconnected was the carb and dist.once reinstalled the cruise functioned normally.and my 84 camaro worked fine untill i removed the computer system then the cruise also quit.i have replaced every component in the camaros cruise system and still wont work.the camaro was taken to mark christopher chevrolet to resolve the issue. i was told by the tech it needed the ecm to work.
 

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There are a couple of grounds for the Cruise system that mount to the firewall, behind the distributor on the driver's side ( Might attach to the rear of the head- can't remember for sure- just know mine were not properly grounded). I would check those grounds to be sure they are good.
 

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Yes the module (CCM) is up under the dash on the right side of the steering column. You will have to remove the small bottom panel containing the A/C vent to be able to slide it out of it's bracket. It is a black rectangular box with AC on the outside of it and a GM part # sticker if it is original. If you do not find your problem with vacuum or grounding you will need to check the wires from this module out to the servo as well.
 
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