I've got a 2005 F-150XLT 4X4 53,000 miles orig owner. Since day one the cruise controls operation has been intermittent. Some days it will work fine, but when it malfunctions it usually goes down like this.

At highway speed, press the "on" button then "set". Sometimes nothing, sometimes I get the green light on the inst. cluster and it holds the speed.
Press the brake to decelerate, then when I try to "set" or "resume" the cruise control nothing will happen. After this if I leave it alone for 10+ min and just keep driving I'll press the "on" button then "set" and it will work fine, sometimes. This happens 60-70% of the time that I use Cruise Control. All my brake lights work fine, and Cruise Control Disengages every time I press the brake so I don't think it is my brake switch, BUT I have not ruled that out.

I have also taken it to the 4 diffrent dealers for a total of 9 times and they say that they can't find anything wrong with it. Any help would be much appreciated!

 

I don't exactly get what the problem here is.

If you have the cruise control on, and hit the brake pedal, it disingages the whole system, pushing set or resume will always do nothing, because cruise control is off. If the problem is that it doesn't come on all the time (intermittantly) not sure there. Is it throwing any codes?

 

Sorry I probably did a bad job explaining...with the cruise control set, I tap the brake the cruise control disengages and the truck begins to decelerate if I hit "set" the cruise control will hold whatever speed I was going when I hit "set". If I hit "resume" I will return to whatever speed I was going when the brake was pressed (the last speed the cruise control was set at). Pressing the brake alone will not turn off the system, there would be no point for an "off" or a "resume" button if that were the case.

I guess to make a long story short one minute my cruise control will work properly the next it will not.

the problem is that most of the time when I do what was described above nothing happens, or the cruise control won't work at all. I have not checked for codes yet, when the dealer said the the diangnostic test were not showing any problems with the system I figured the hand held ones would do the same. thanks again!

 

Did you ever get any info on this?
my 06 just lost its cruise function as well. Mine isnt intermitent though, it just doesnt turn on. It was working perfectly fine up until two weeks ago, i tried to turn it on and nothing happened....
My first thought was the buttons, but my radio buttons are still working properly. i know they share a power feed, so they have power.
Any Ford techs here that can tell us how to diagnose the problem?

 

+1 on the newer f150's.

 

Have you checked your third brake light? I believe if it is burned out (or not working due to corroded contacts) that the speed control will no longer work.

Failing that as a cause, if the truck "thinks" the brakes are applied, the speed control is turned off. So, I'd try to locate and adjust the brake light switch if it's not the third brake light.

- Jack

 

Thanks jack, thats exactly what happened. I did some searching on here and thats exaclty what was wrong. I replaced my third brake about a month ago, and hadnt gone out for a while so i didnt even think of it being the reason. I already have led tail bulbs so with the added LED third brake it did that. I fixed it last sat with a spliced in bulb and harness. I figured this was better than those awfull LED resistors that heat up to five thousand degrees.

 

Good call Jack.

 

Let's see, that's one "atta boy" out of how many "aw sh*ts"?

- Jack

 

So basically I will be able to tell when my third brake light is burned out because my cruise will no longer work?>

 

are you serious? hell, you learn something everyday

 

This is more so the same route as if you do not have brake lights, you cannot take the truck out of park.
If you pull all 3 brake lights, the shift interlock should not work any more ( need to turn the key to the on position, move to neutral, and start the truck there, then you can move to Drive / Reverse ).

With all 3 stop lamps as LEDs ( and no load resistors ) the shift interlock still had enough to work, but the BOO logic saw it as dead stop lamps( ABS might not have worked in this case either ? ), and the CC fail safe acted.

I pulled my CHMSL bulb, but put the aftermarket LED CHMSL on the cap back onto the circuit, with standard tail lamps bulbs, and my CC works ( ABS too, rain then snow yesterday, they worked over time ).

 

Boy, sounds like Ford doesn't want you driving without brake lights. Great piece of information, SSCULLY! Wonder if all new vehicles (from other manufacturers) work this way? Interesting though that you can get it out of Park with the key ON if the engine is not running.

I still have regular bulbs in the tail lamps, but since I have a cap that covers it, I took all the bulbs (bed lights and 3rd brake light bulbs) out of the high mounted cab light. Then I remembered the CC might not work without a bulb and I put a spare LED I had there. Thinking about it now though, I wonder if it was necessary. My cap has a high mounted brake light too, and if it's wired to the 3rd brake light circuit, I could just leave the cab light socket empty. (I was trying to reduce the electrical load from useless lights).

I guess I could always unplug the cap light and see if the cruise still works.

 

I never got any more info on my problem, but its still acting up. I'm taking it in next week and maybe the dealer can figure it out this time.

 

Sorry we couldn't help you with your problem mcouv. I agree, it SHOULD "resume" the previously "set" speed if you press Resume after tapping the brake pedal, mine does. And, it should set a new speed if you push the "Set" button after tapping the brake pedal (assuming you have not pushed the Off button before you push either the Set or Resume buttons). Sounds like the brake is turning the system completely off, instead of just releasing the speed.

The only other thing I can think of is that your brake switch is set too sensitive or the pedal return spring is weak and if you tap the brakes, the system "sees" them as being constantly applied for a while. Have you tried pulling up on the brake pedal with your toe when Resume doesn't work to see if that might "fix" the problem?

I'd get a "parking brake warning" at times while driving my previous truck (a Nissan). Just pulling the parking brake pedal up with my toe fixed it.

- Jack