Cruise Control issue

[Hilltop123]

03' Dodge, 3/4 ton, 4x4, diesel...............Go to set the cruise control, and it is real slow to engage, when it does engage, lack the strength to keep the throttle down....in short:   Works on the flat, but craps out going up grade.....any ideas?

[jackelope]

Stock truck? Big tires? Auto transmission?

[Hilltop123]

Everything is stock, never been chipped, that I'm aware of........auto trans.............But I did just read something interesting, about how aftermarket rear lights will affect the cruise control.....guess what, I just had the truck in the shop, for some rear panel work, and the shop replaced the light.....HUMMMMMM

[jackelope]

I never heard of that other than brake lights. Same switch turns on your brake lights and turns off the cruise when you hit the brakes. Brake lights stuck on=cruise control inop.

[dewandgin]

On some vehicles they use the brake light bulbs as a ground circuit or the resistance in the bulb for a input. If someone happens to put LED brake lights in it the cruise will not work. Spent almost 5 hrs on a ambulance headed to Alaska before I figured this one out. It was a 09 Ford Chassis cab.

[Mudman]

Uh, TPS?

[smalldog]

Your cruise control issue,         Sounds like you have a small hole in the diaphram that works the troddle.
If this is a dessel truck then it probably a vacum problem.

[coachcw]

yup lack of vacuum , check the supply to the servo .

[h2ofowlr]

What's cruise control?  I live in western wa and it's stop and go or speed up and slow down.   

Probably vacuum as mentioned.