Cruise control turns off when I remove my foot from the accelerator pedal

2002 FORD F-350
200,000 MILES • 7.3L • V8 • TURBO • 2WD • AUTOMATIC
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TREEBARK1
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I have the truck listed above diesel. The cruise control will turn on and function until I remove my foot from the accelerator pedal at which time it will immediately turn off. It works flawlessly until I take my foot off of the gas pedal. I have replaced the cruise control cutoff switch on the master cylinder and the VSS on the rear differential and it still behaves in the same manner. The speedometer and horn work flawlessly. What could be the problem?
Feb 6, 2019 at 5:36 PM
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SCGRANTURISMO
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Hello,

This sounds like it could be a problem with your speed control servo. I have included a step by step troubleshooting guide in the diagrams below. Please run through it and let us know what you find out. If more help is needed we can go from there.

Thanks,
Alex
2CarPros
Feb 8, 2019 at 5:58 AM
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TREEBARK1
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Thank you for the quick response! I am sorry about the delayed reply but I was working out of town. I read your suggested diagnosis but don't think that my particular truck actually has a cruise control solenoid. The gas pedal doesn't have a cable attached to it but has an electronic position sensor. I did a search for the solenoid but came up empty. I have also actually replaced the motor in this truck and have never encountered a cruise control solenoid. I know what you are referring to because I have seen it in other cars with throttles controlled by cables but I think that my cruise control must be controlled electronically. I surmise that my problem must be related to the position sensor located on the gas pedal as my cruise control has complete functionality until I fully release my foot from the gas pedal, but don't want to just throw money at parts as I have already replaced the most common parts associated with my problem and the problem still persists. Thank your for your response and let me know if there is anything else that I might check to help solve my issue. Thank you!!
Mar 1, 2019 at 2:45 PM
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SCGRANTURISMO
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Hello again,

So, I re read your first question to us and I believe that the problem probably lies with the speed control switch. When you have your cruise control on and hit (set/accel) button the cruise control should be engaged, allowing you to take your foot off the gas pedal. If you let your foot off the gas pedal and your cruise control is not engaged then it has to be in this circuit. Check fuse f2 27(15A) in the central junction box. I have also included another test if the fuse is good, location information and a wiring diagram for you in the diagrams below. Please let us know what you find out.

Thanks,
Alex
2CarPros
Mar 2, 2019 at 12:57 AM
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TREEBARK1
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I will do the recommended checks and let you know. Thanks!
Mar 4, 2019 at 2:55 PM
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STRAILER
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SCWICKEDSTANG is one of our best! Please let us know what you find. We are interested to see what it is.
Mar 7, 2019 at 10:15 AM
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TREEBARK1
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Sorry it took so long to reply but I just got back from out of town and had a chance to check the truck. I did find the problem and I don't think anyone would have been able to diagnose it without actually seeing the truck. To set the stage, I am not the first owner of this truck and when I bought it, there were two toggle switches installed on the dash that I thought did nothing because when I switched them, nothing happened. Well, when I went to check the fuse as recommended in SCWICKEDSTANG's reply, I noticed that the switches were wired into the gas pedal and then the wires went out into the engine bay where they were attached to a relay. Then the wires went to the cruise control cutout switch on the master cylinder and back to another relay. Then there were a couple wires coming off of that second relay that had been cut off and left. Once I removed the aftermarket wires from the cruise control cutoff and put it back to normal, the cruise control works just fine. I am not sure what the original purpose of the wires and switches was but now everything works fine. Thank you for you time in helping me diagnose my issue! Your recommendation to check the fuse is what led me to figure out the problem. Thank you!
Mar 22, 2019 at 4:21 PM
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STRAILER
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Glad you could get it fixed, that kind of problem can be tough. Please use 2CarPros anytime we are here to help.
Mar 23, 2019 at 2:32 PM