Cruise Control Problem

[Jack in Alaska]

On my 10th trip from Alaska to Arizona this week. Towing a 11k lb. travel trailer.



When using the cruise on level ground it works fine.



When starting up an incline and the engine starts to work harder the cruise drops out suddenly and makes the whole truck shake for an instant.



I quit using it for now. What is the problem??? Any ideas or help out there??



Thanks.



In Kingman, Az. tonight.

 

[hcole]

It may be vibration from the engine and trans shaking the brake pedal. Try going up the incline and using your foot to pull up on the brake pedal to hold it against the brake switch when using the cruise.

 

[Jack in Alaska]

No more ideas on this question????

 

[ata]

It sounds like low vacuum to me. Put a gauge on it and see if the vacuum is dropping out and fluctuating. On the level its not needing a lot of vacuum but when you hit a hill it has to have more vacuum to pull the throttle a lot more.

 

[cerberusiam]

Do you have Cruise Control or Speed Control?

 

[Jack in Alaska]

cerberusiam... ...
It is a 2004. 5 RAM which is probably the same as your 2005.
Jack

 

[cerberusiam]

Jack, you have either an engine mounted APPS or under the drives side battery. The 05's speed control are all in the ECU as there is nothing in the engine bay.

If you have cruise control then you will have the cruise module and it likely uses vacuum to run it. If you have speed control it should be in the ECU and that would point to an APPS issue.

Manuals usually have speed control but thta is not a hard an fast rule, need to check and see if you have a CC controller and cable to the APPS. Could still be an APPS issue on CC.

 

[Axekicker]

On my 10th trip from Alaska to Arizona this week. Towing a 11k lb. travel trailer.
When using the cruise on level ground it works fine.
When starting up an incline and the engine starts to work harder the cruise drops out suddenly and makes the whole truck shake for an instant.
What is the problem???
Thanks.
In Kingman, Az. tonight.

********************************************
Jack, I had the same problem with my '04.5.
It was a worn-out vacuum pump and at least two vacuum line leaks.
The cruise-control works off an under-hood vacuum pump
After installing a new vacuum-pump and some new vacuum lines...the cruise works perfect.
That was about a year ago....it's been fine ever since.