This has happened 3 or 4 times now while driving down the road. Just cruising down the road the CC will just cut out. I'll hit the "set accel" button on the wheel and all is good again until it randomly decides to do it again.


The only thing I've changed recently is the rearend speed sensor to cure the ABS light. I wouldn't/didn't think this would have any effect on the cruise control, but IDK, maybe i'll put the original one back in and test it.


Anyone experience this before?

 

I'm thinking it could. My wife's ford 500 had a brakelight socket with an intermittent short. It would do the same thing. Car thought you were tapping the brakes when it hit a small bump. Took me forever to find it.

Denny

 

The "Usual" suspects are the E-Brake Switch and the Foot Brake Switch. Although, the speed input sensor also is in the arena; just not as often.

 

Mine does this when I hit a bump, just haven't replace brake switch.

 

There was a recall regarding Cruise Control... Not sure of the number for it but I had mine done a few years ago... Might look into it..

 

The recall was for a faulty wiring harness which in actuality did not affect Diesel Units, but they were included as the Manufacturer Unit "F-Series".


The recall did not affect Cruise Control function.

 

Good information, I had mine done because I heard of a few trucks that the CC wouldn't shut off!!!

 

Perhaps that depends on which "recall" is being referred to?

The recall that comes to my mind for the Speed Control Deactivation Switch (SCDS) is directly related to cruise control. Speed Control and Cruise Control are synonymous, no?

And the recall I'm thinking of definitely applied to diesels. I received several letters in the mail from Ford about it. My truck's OASIS report indicated that my diesel VIN needed it.

There is a concurrently active thread about the SCDS recall here: https://www.ford-trucks.com/forums/8...l#post16294048

At the end of the thread linked immediately above, there are three hyperlinks to Ford and NHTSA websites where one can enter their VIN to see if this recall is applicable.

 

NONE of these address any concern on the Diesel Platform. These trucks are included because they are F-Series platforms by the complainant (NHSTB).


Ford will perform both recalls on Diesel Platforms ONLY because they are the F-Platform Vehicle.


Diesels provide NO POWER to either switch when in the OFF Position. Power to the CCIF is from the PCM and NOT the CCM on Diesels for the second recall.

 

It simply never occurred to me before to question whether or not the recall would apply to my diesel chassis cab, especially after Ford sent no less than four written letters to me by snail mail, urging me to get the recall done. (Ford didn't realize that I had already taken care of it myself).

However, since you raised the point, I tested the harness, and can confirm that you are indeed quite right. There was no power at the switch with the engine off. With the engine running, there was power at the switch. This is on my diesel chassis cab. Thanks for the correction. Reps sent. (whoops, looks like I've already repped you for something else recently... someone else git him for me will ya?)

I also have a gas V10 cutaway. I received letters on that truck as well. It isn't convenient for me to test that vehicle right now, but when it is, I will report back to confirm whether or not the SCDS is exposed to constant hot with the engine off or not. I assume that it will be constant hot, as described in the recall, since it is a gas vehicle with vacuum assisted brakes rather than hydroboost. But hey, I learned something new today... perhaps I'll learn something new tomorrow as well.

In the meantime, diesel or not, hydroboost or not, we know that the original Texas Instruments SCDS switch was known to have a membrane failure inside. For the original poster whose cruise control suddenly cuts out, as if the brake pedal were to be depressed, the question remains... if the SCDS was faulty, would replacing it correct the OP's reported condition?

For less than $20 bucks, and with the problematic history of the failing membrane in the original SCDS, I would think replacing it would be a good idea anyway.

 

When my speed sensor went out the cruise control went out to. But with mine so did the speedometer. Is your OEM sensor?

 

If there's power to the switch at any time, isn't there still a fire risk if the membrane ruptures?

 

Using the above information i would think we can say that the diesel is still a fire risk but that you would be in or near the vehicle because it would be KO. At least they won't catch fire in your garage while you're sleeping.

 

No, The issue was that there was no "secondary protection" or in this case no protection device to de-energize the circuit as there is when the system is operational.

Any number of three fuses and additional sensors could have failed thereby preventing the fires. But, this in ONLY during KOEOn Operation. In KOEOf no additional protections were available to disarm the circuit.

"B.L.U.F.: "The subject wiring had no protection and was energized all the time thereby causing an overheat situation in that circuit. Failing insulation exposed an electrical circuit that, if unchecked ignited combustibles within inches."

You can find out more about the "Cause and Origen" of the Fires at the National fire Protection Association Archives.


(If you want to test this hypotheses as we did. Find any gasoline platform and touch the wire to ground from the circuit while the ignition is off. The wire will immediately glow red and burn anything it touches).

With a Safety Recall of this magnitude and possibility for loss (people were loosing their homes from garage fires and a loss of life was also reported), ALL F-Series Platforms (amongst 7 other platforms) were recalled by the manufacturer. Regardless of the Powertrain. Although, Diesel Platforms did NOT require the part, it was replaced under the same recall.

I personally reported for one agency on this during the timeframe and was an appointment of the committee. Of the seven vehicle fires that this was attributed to, over $19M was lost in vehicles and adjoining structures and that was in just one county in one state.


You can see why Ford acted so swiftly and included all platforms with this wiring immediately once a connection was established between the circuit and fire being reported.


This a side, I can only imagine the air bag recall before its done. I bet it will reached decades back and eventually includes most all vehicle in the World.

 

I really don't believe Ford would have expanded the recall to specifically include diesel equipped vehicles if there was zero risk of fire.