Goofy Cruise Control

[Gizmo 007]

I took a trip to Corsicana TX today (hilly country). I got on I45 and set my cruise on 75. Coming down a hill, the cruise would hold a steady 75-76. Going up a hill, the truck would lunge and accelerate to over 85 ! What could be happening? I unplugged my EZ but it still did it. Any TSB's or fixes for this? I'm curious if anyone else has had this happen.

 

[Straight6Jeff]

AAAHH Yes, the infamous cruise problem. Sounds like your servo is going bad. Mine would keep gaining speed til about 95mph. But first, I'm not sure where the servo is located on the diesel, but if it is under the battery, check the vac hose for contamination or dry rot. The batteries tend to leak directly onto the hose. At least on the v-10 they do. Mine was doing the same thing and it would also loose sped at times, but that turned out to be a brake sensor switch. On the plus side, the servo is only $65. Most dealers have them in stock because it is a common problem.

 

[Shelby Griggs]

The 2001. 5's and later do not have a servo or any mechanical connections for that matter. All controlled electronically from the ECM. Sounds like a software problem.



BTW, my speedometer and cruise are the most deadly accurate of any vehicle I have ever owned. My speedometer is right on as checked by GPS and the cruise will stay at a constant speed within about ½ MPH all day long on the flats. A little variance in hills, but not much.



It does seem to me that I have had an over speed once or twice when resuming, but have never had a problem with cruise once activated.



Shelby

 

[Straight6Jeff]

Thanks ofr the claification on the servo thing. I didn't relize that diesels didn't have them. I learn something new every day on this board. BUT, for anyone who has a gasser, the servo is a common problem. What I don't get is why do the vehicles come out of the factory with garbage parts, then have identical part numbered pieces put on and they work fine. The cruise problem of gassers has been an issue for many years.

 

[Shelby Griggs]

Originally posted by VeeTenJeff

Thanks ofr the claification on the servo thing. I didn't relize that diesels didn't have them

Prior to 2001. 5 the diesels did have them, same as the gassers. The original question related to a new Ram, shouldn't have the servo on that one.



Shelby

 

[Gizmo 007]

Brought my truck in to the dealer this am. Nice guy at the service center. Said it was the second truck that he has seen do this. He erased my ECM the reprogrammed it, all better now. he claims it was a software glitch in the computer. No ill effects of the upgrade... yet.



Thanks guys