I bought a 2005 Sort Trac last year, 200.000+ miles. I have an occasional problem with the speed control. When I turn it on and try to set it some times it will work right away and some times I have to drive 5 or more miles before it will engage. Also if is engaged and I have press my brakes suddenly(some one pulls out in front of me) then about 90% of the time I am back to driving 5-10 miles before it will engage again. Anyone have any ideas? Thanks.

 

Please try to warm up the car, like idling for 10 minutes before you start driving, let us know the result if there is any improvement on your speed control when doing so, then we start from there and I will submit the diagrams and how to troubleshoot this.

 

I believe I have tried that before but I will try it again, but because it is an intermittent problem it may be awhile before I know. Thank you for your reply and help.

 

I know it is an intermittent that's exactly why I need to confirm something so please try it just ONCE, not that you should do it all the time from now on.

 

I went to town today and I let it run until it reached the bottom of the gauge, it was too hot out to let it idle much longer than that.I did not have a problem with it today.But then I may go several days without having a problem than it will start up again. My only thought is it has something to do with the brake pedal or the pedal sensor but I could be wrong about it.

 

When you start up your car (cold) the vacuum is low and as it gets warmed up, the vacuum will become higher. The higher the vacuum the better for CC to operate. If there is a vacuum leak it will take much longer (if at all) for your CC to engage. The service manual did not mention all these, your symptom tells me there is a vacuum leak for the slow CC engagement. That's exactly why I asked you to warm up your car in the previous message. So please check the vacuum linkage from C122 to intake manifold, as well as vacuum leaks elsewhere.
This pic shows the location of C122.

And here's the diagram of C122:

You just need to remove the electrical connector. You probably don't need the C122 removal procedure diagrams, but please ask if you do. You can perform most of the tests right at C122. Please do NOT blindly buy the cable, it's $100+. Download 4.pdf and 5.pdf below should get you started.
Here to locate C1025 (brake pressure switch):



Here to locate C278 (Brake pedal position switch)

C278 is adjustable, so don't blindly buy a new one. You should know your brake switch(es) are for CC disengagement, and you are having problem with CC engagement but a "sticky" C278 can make your C122 to think that your brake is currently depressed, not allowing CC engagement as a result. There is also other check you can do quickly like checking your brake lamp does it respond immediately when your brake pedal is depress/release.
Please ask if you need other diagrams since they are too large to attach all of them to here.

 

Thank you for the information, the pics did not come through but I found a diagram on line showing C122 and I downloaded the PDF files.I will look into it later this week. I have an appointment tomorrow. I will start with that then move on to the brake light switch. I appreciate the help.

 

4 pics attached inline to the message, 3 pdf you can download on the bottom. If you can't see the pics try to reload this page.

 

My apologies I have not been ignoring you but I have not been feeling very good lately. I hope to try and get on this over the weekend.

 

I was finally able to get out there and look at it, I re-read the instructions but I am afraid it may be a little beyond me. While I have done a lot of maintenance on my vehicles over the years not much of it was electrical. I am looking at where it says to connect a diagnostic scan tool, which I dont have then drive it at 30 miles p/hr which I a, not even sure how you would do that. I am going to see if I can find someone to help me. Until then I will just have to deal with it. I thank you for the help you have already have given me.