Cruise control works when it want's to...so annoying

[reese600]

So I have an intermittent issue with my cruise control. the power button on the steering wheel works. I have a 50/50 shot that if I hit SET, that the cruise will work. I drove 6 hours today on the highway, cruise set and worked fine, got off an exit, stopped at a stop light, took off, got back up to speed, tried to set the cruise, and nothing, no green light on the dash, nothing. This happened minutes after I got off the highway, its driving me nuts.
Changed the clock spring and brake switch, OEM parts, and it still does the same damn thing!! When it works, it works exactly like it should, and when it doesn't, the LED is still on the power button, but it doesn't engage? This has been going on for months now.
Any ideas? Where is the cruise control located? Part of the BCM or ECM? I have the GMT_900 electrical manual, and I've tried to find the cruise control circuit so I can start checking wires, but I'm not finding much info, it's 670 pages

2009 Chevy 2500 HD LTZ CCSB w/ 07 LBZ engine, 338,952 miles

 

[Chevy1925]

did you check the brake switches like i stated in your other thread?

 

[reese600]

Yes I replaced the brake switch after I tried the clock spring, same results.

 

[BLACKMAX1]

Could be the BCM since mine also needs to be replaced and I was having a similar issue with cruise. Still haven't replaced the BCM but after I flushed the trans and changed the internal/external filters and cleaned the harness plug at the drain pan I haven't had any further issues with cruise control.

 

[JoshH]

You should be able to use a scan tool and verify if the buttons are functioning properly or why it is inhibiting cruise if the buttons are working.