Chasing a cruise control failure to engage.

[Bill 1960]

Just checking to see if there’s anything else I should check before I take it in to the dealer. I’ve checked what I can, but I don’t have a Tech 2 to scan the inputs.

Symptoms: Orange indicator on the steering wheel lights up when CC is turned on. Nothing happens when pressing the Set button.

Diagnostics to date: I reviewed the wiring schematic and there’s not that much to it. The brake switch, and the controls on the steering wheel. The brake switch tested good with a VOM. I replaced it anyway since it’s cheap and a common failure. No dice.
I disassembled the steering wheel and tested the switch pod there using the method and specs from the service manual. All switches function and resistance levels are exactly on spec.

My suspicion is perhaps a damaged wire when they decommissioned the SSV and got busy with the wire cutters. At this point I’m running low on time before other activities require my attention, so I figure the best thing is let the dealer go at it with a Tech 2 and see what’s up.

Unless there’s another thing I should have checked and didn’t?

 

[donjetman]

Believe it or not? brake pedal stop light switch fixed this same problem for me. NAPA Part# SL1000 - $19

 

[kbuskill]

Where are you located?

Perhaps someone here on the forum is relatively close and has a Tech 2.

I know you said you have replaced the brake switch but have you tried lifting the brake pedal with your foot while trying to engage the CC?

 

[swathdiver]

The brake switch tested good with a VOM. I replaced it anyway since it’s cheap and a common failure. No dice.

Gotta use an OE or ACDelco Professional one, aftermarket ones usually don't work. Neither does trying to clean the connectors on the old one. Don't forget, new parts can be bad too.

If that doesn't fix it and you have no codes, then it is the module on the steering wheel. 99% of the time it's the brake switch.


25981009 D1539J

 

[Bill 1960]

Yeah, the brake switch is OEM, and both sets of contacts are switching properly when the pedal is depressed. There’s two circuits in the switch, one to the BCM and one to the ECM if I recall correctly, and cruise requires both to be in the correct state. Which they are.

 

[Bill 1960]

In closing, it turned out to be a short in the clock spring. Tech said it was sending a “set” signal to the computer constantly rather than only when the button was pressed. They replaced that and all is well.

 

[petethepug]

Interesting, that was probably the issue with the heater on the steering wheel of our last 08 Denali XL.

It’s probably a good call to have the dealer preform that job. If a new code pops up after swapping out the clock spring, it’s the dealer/techs responsibility to chase it down. Now you’ve got a 1 year warranty on it too.

Do you have an airbag recall pending too?


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[Bill 1960]

@petethepug yeah, I’m somewhere in the queue for a new airbag. Service guy tells me they’re sending out letters to owners and wait for that. Lots more demand than airbag supply so they’re allocated.