Whats wrong with my cruise control?

[John Zuber]

My cruise control works about 50% of the time...when it does work it works without any issues. Engages immediately, disengages when using the brake, reengages, can turn it off and then back on, etc, etc. However, when it doesnt work, it wont engage. The indicator light will blink or flash with the act of pushing the set button, but it wont engage or catch. Ive tried turning it off and then back on, tried tapping the brake to see if maybe the switch is hung up...no results. It almost seems as if the system is just dependent upon a status associated with operating the vehicle. Ive never tried just pulling over and re-starting the truck, but that almost seems what its associated with. Any ideas where to start?

 

[EddieS'04]

Your profile is not complete. If you have a gen1 trac. Most likely the switch on the end of your master cylinder is bad. There is a project on how to replace it.

 

[bob k 2]

on my 04 trac i had the same issue. changed the battery and haven't had a problem since. just a thought.

 

[Mark K 2]

Low brake fluid.

 

[John Zuber]

Sorry...my ST is a 2004 2WD V6. What is brake fluid and battery...ok, just kidding. :cheeky:



Brake fluid is at the proper level and battery is about 2 years old. I don't see how the battery could be the issue since it seems strong and the CC is being operated when the battery is being charged. Is the switch on the master cyclinder only related to the CC?

the end of your master cylinder is bad. There is a project on how to replace it.

What folder is that project filed under? Thanks

 

[Bryan Tobey]

x2 on the cruise control switch in the master cylinder. It's the most likely culprit. Good luck!

 

[EddieS'04]

What folder is that project filed under?

 

[John G]

"Most likely the switch on the end of your master cylinder is bad"



Is that the switch that was the subject of a recall a couple of years ago? I remember getting mine replaced because of a risk of fire.

 

[Chris Taylor]

+1 what others have said. However, I had the same problem last spring and getting out and using the cruise control seems to have cleared up the problem. I don't drive the ST as much, or use the cruise as much in the winter, and I think that valve was just sticking. It's worked ok all summer. It may be the cold weather, but I'm thinking it was just sticking due to little use.



So maybe if it has sat a while, or you have not been using the cruise a lot, it may just have to get unstuck... I'll let you know if mine starts to stick as the weather turns cold.

 

[John Zuber]

The price is $40 from the local Ford dealership. I wish I fully understood what this thing does, so that I could do some testing to be sure its defective. Also, wonder if it could be cleaned...and if that would help. I know this may sound strange, but back in the 80's I purchased a used 86 ford Aerostar...wow, wonderful van. Went over 230K when traded in. Anyway, when I got it I flushed the brake fluid out and actually pulled the master cylinder off and cleaned it with hot soapy water. Finished by flushing with brake fluid. That unit and fluid was always clean after that and I never had a master cylinder issue with that van.

 

[EddieS'04]

John it is a pressure switch. It is normaly closed. It completes the circuit. If you step on the brakes, the switch opens the circuit.

 

[Bryan Tobey]

oreillyauto.com shows the motorcraft switch for $29.99



Fast Parts Network (site sponsor) shows the switch for $29.30



Just saying, why spend $40 at your local dealer?

 

[Mark K 2]

Don't know if generic switches are available, but this is one of those instances where you want to use a Motorcraft product.

 

[John Zuber]

oreillyauto.com shows the motorcraft switch for $29.99



Fast Parts Network (site sponsor) shows the switch for $29.30

thanks...agree