Cruise control

[Cwrhyne]

2011 Yukon XL 1500 5.3.
I had a brake booster installed and master cylinder and when it came home the cruise control doesn't work. The mechanic sent me a picture of a red wire coming out of the main harness and said this looks important. Can anyone tell me what this is where it goes and if it has anything to do with why my cruise would not be working

 

[Doubeleive]

2011 Yukon XL 1500 5.3.
I had a brake booster installed and master cylinder and when it came home the cruise control doesn't work. The mechanic sent me a picture of a red wire coming out of the main harness and said this looks important. Can anyone tell me what this is where it goes and if it has anything to do with why my cruise would not be working

that is the factory wire for either the installed brake booster or it goes to the tow hitch to provide power to a attached trailer I don't recall which.
in either case it attaches to one of the studs in front of the fuse box

 

[Fless]

I don't think that's for a brake booster. Trailer brake controller, probably (or aux power to a trailer as mentioned). Nothing to do with cruise control.

 

[Doubeleive]

I don't think that's for a brake booster. Trailer brake controller, probably (or aux power to a trailer as mentioned). Nothing to do with cruise control.

trailer brake control is a brake booster, at least that's what I have always refereed to them as
not to be confused with the master cylinder.....

 

[CaptainAmerica1]

Brake booster is that big metal thing between the master cylinder and the firewall. Get your terms straight. You’re gonna confuse the newbs….

 

[Fless]

I would suspect an issue with the brake light switch that's attached to the brake pedal lever. Mechanic would have been there with the brake fixes...

Do the brake lights work?

 

[Cwrhyne]

I would suspect an issue with the brake light switch that's attached to the brake pedal lever. Mechanic would have been there with the brake fixes...

Do the brake lights work?

Yes sir. Brake lights work. Cruise fuse is good too

 

[swathdiver]

2011 Yukon XL 1500 5.3.
I had a brake booster installed and master cylinder and when it came home the cruise control doesn't work. The mechanic sent me a picture of a red wire coming out of the main harness and said this looks important. Can anyone tell me what this is where it goes and if it has anything to do with why my cruise would not be working

That's the "hotel" for the trailer, providing 12v to power a trailer's interior lights, outlets, etc. It is normally taped up under the brake booster and when put to use, connects to the right stud at the front of your fuse box.

It does not have anything to do with your cruise control not working.

Now when you turn the cruise on on the steering wheel button, does the amber light come on? If it does, the usual suspect is the brake switch under the dash... wait, those guys were working down there to change the booster. They might not have plugged it in or plugged it in properly.

Here's what it looks like. Always good to keep a spare on hand (D1539J or 25981009):

 

[Cwrhyne]

Thanks y'all. Still need to figure out cruise control though...

 

[Fless]

Thanks y'all. Still need to figure out cruise control though...

That's pretty much what @swathdiver was pointing out. The brake switch has three internal switches, and one is for the cruise control. See if it's properly connected. After that your mechanic may need to run some diagnostics.