Cruise Control not working

[Ohmoxide]

My cruise control light comes on when I turn it on, but it will not engage. No fuses are blown.

2003 SLT Quad Cab with the 5.9L diesel, bought used a couple years ago.

Thanks.
-Rob

 

[MikeT]

The brake switch went out on my 06, and caused the cruise control to be intermittent or to fail completely intermittently. You could have the same problem, fairly common.

Mike

 

[justin13703]

Another vote for the brake switch. It’s easy to check with a multimeter but I’m willing to bet that’s what the problem is.

 

[Ohmoxide]

It feels a bit sticky, I will replace it and hope that fixes the issue.
Thanks.
-Rob

 

[Ohmoxide]

Another vote for the brake switch. It’s easy to check with a multimeter but I’m willing to bet that’s what the problem is.

If it is broken, will it read no resistance or an open circuit?
-Rob

 

[justin13703]

Normally you would just find the two brake pins and check for continuity. Should be closed with the switch not pushed, and open with the switch pushed. Cruise would be the opposite, open with the switch not pushed, and closed with the switch pushed.

Unfortunately it looks like, in typical dodge fashion, they over complicated another simple thing and used a switch with a ton of contacts that is tied in to two or three computers, and I can’t find an accurate wiring diagram for that switch. So it’s hard for me to say which terminals to test without having it in front of me. When they’re broken, they will usually show an open circuit all the time, or a closed circuit all the time, regardless of the position of the switch.

 

[Ohmoxide]

Wow, well thank you Justin, I guess I will just buy a new one and hope for the best.
-Rob

 

[Ohmoxide]

Okay, I replaced the OEM brake switch with a new aftermarket switch. The cruise control is still not working. "Cruise" light still comes on the dash but it will not engage.

On a positive note, brake lights still work correctly.

What should I try next?

-rob

 

[justin13703]

Okay, I replaced the OEM brake switch with a new aftermarket switch. The cruise control is still not working. "Cruise" light still comes on the dash but it will not engage.

On a positive note, brake lights still work correctly.

What should I try next?

-rob

Dang man that sucks. That would have been the most simple thing. The only other things I can think of are, there may be a problem with the cruise switch, or there may be a problem with the cruise actuator. However I’m not exactly sure how to test these because I have an 08 with all the electronic throttle controls. I believe since your truck is a diesel you should have a line running from the cruise actuator to a vacuum pump. You could check that line and make sure it isn’t cracked or broken.

 

[Ohmoxide]

Okay, vacuum line shall be checked next, thanks.

 

[Ohmoxide]

I should add that the truck has had other electrical issues, the passengers can not roll down their windows, but can unlock the doors.
Maybe this will help pin point the problem.

 

[bulrid8]

I should add that the truck has had other electrical issues, the passengers can not roll down their windows, but can unlock the doors.
Maybe this will help pin point the problem.

The window problem is most likely a broken wire in door loom. Either passenger or drivers door. Very common on these years. Its a pain, but you can pull it apart and splice any broken wires.

Sent from my SM-G955U using Tapatalk

 

[Ohmoxide]

Thanks Bulrid

 

[Brando_SLT]

Chiming in, I am having the same issue with my cruise control. I can push the button to turn cruise control on, but accelerate/cancel buttons don't work.

Brake pedal switch is working - how complex is the cruise control unit on our trucks? I still need to get a copy of the workshop manual...