2008 Silverado Cruise Control Problems

[bigj-dog]

Hi, a friend's '08 with about 60k on it has been having sporadic issues with the cruise control for a few months, now it's no longer working at all. The on/off switch seems to be operating, but nothing happens when the set button is pressed. I'm assuming the sporadic nature signals a short, but any ideas where? The brake lights seem to function normally, and he hasn't complained about any other issues that I'm aware of. Thanks for any input.

[MT-2500]

Originally Posted by bigj-dog

Hi, a friend's '08 with about 60k on it has been having sporadic issues with the cruise control for a few months, now it's no longer working at all. The on/off switch seems to be operating, but nothing happens when the set button is pressed. I'm assuming the sporadic nature signals a short, but any ideas where? The brake lights seem to function normally, and he hasn't complained about any other issues that I'm aware of. Thanks for any input.

As always check all fuses.
Check wiring and plug ins.
If all else fails get it on a body abs engine computer capable scanner and read out data and do test and check for codes.
Post back any codes.
Let us know how it goes.

[4x4junkie]

throttle positioning sensor going bad can cause to work spuratic, and if it went out completely it would stop working, however it could be a fuse issue intermitten when loose, which would eventually blow the fuse and make it stop working, also the speed sensors at the front wheels, or the vss in transfer case on 4x4 or vss at transmission on 2 wheel drive.

[4x4junkie]

a more specific note: the VSS informs what speed the vehicle is moving and works with the throttle positioning sensor to maintain the vehicle speed, since the vss also controls the antilock braking system (which was not noted in having issues along with help of the front speed sensors located at the front wheels), i would lean more towards the throttle positioning sensor, this sensor is located on the throttle body directly across sides from the accelorator linkage). A diagnostic tester should be able to tell if the throttle positioning sensor is performing corrrectly. take the vehicle to your local auto parts store and ask them to read and see if there are any codes present. if so list the code here many of us have manuals that tell what these codes mean.

be sure to list anything you do in details and we will be glad to help further with the issue.

[bigj-dog]

Great info, thanks a million. I'll ask him if the ABS has acted up, and I have a scanner that can check the throttle position sensor operating range. I have an actron abs scanner too, but I'm not sure if it'll work on a truck that new. I'll get into more detail with my friend tomorrow. He bought it new, and hasn't been real happy with it overall, but I can't remember the other issues, but I know the cc has been plaguing him for quite a while.

[wamaroe]

Recently had a neighbor bring me his 2010 Suburban 5.3L for two problems. 143,000 miles. Cruise buttons on the steering wheel were working, but dash would not light up. It wouldn't hold a speed when hitting the Set button above 25 mph. Fix was $13 brake switch from R/Auto. It's located on the brake pedal.

[wamaroe]

Recently had a neighbor bring me his 2010 Suburban 5.3L for two problems. 143,000 miles. Cruise buttons on the steering wheel were working, but dash would not light up. It wouldn't hold a speed when hitting the Set button above 25 mph. Fix was $13 brake switch from R/Auto. It's located on the brake pedal.

[Blue Bowtie]

For reference, on many GM models the cruise will not engage if the third/center brake light filament has failed. The system uses the load of the light to pull a sensing voltage low as a secondary check to see if the brake pedal is depressed, just in case the cruise switch for the brakes pedal is knocked loose or fails.

[wamaroe]

Thanks Blue Bowtie. Someone on another string referenced a brake light being out would keep cc from working. Never heard an explanation of why & how it works that way tho. Knowing how the "black box" mystery works is tantamount to a successful repair.

[TerraTrax]

Thank you Blue Bowtie! You may have just answered my question as to why my cruise control doesn't work. I installed an LED high mount light in my 2000 Silverado and I didn't put a load resistor on it.

[327chevy]

I had issues with the cruise on my '08 not working and I took the brake pedal switch off, cleaned the contacts up and put it back in. Cured the problem for a while but I eventually just put a new switch in. Problem.solved.