Diagnosing Cruise Contol not working

[cmore]

Trying to diagnose cruise control not working on my 03 RS6.

It doesn't work any of the time and never engages.

Here's what are the options that come to mind:

* Brake light switch
* Control box
* Steering wheel stock

So, here's where I am:

* if I press on the brake pedal, the rear brake lights turn on, so should I rule out the brake light switch?

* I am able to start the car in park without pressing the brake pedal. Is that normal with other RS6s or C5s in general?

Thanks,
Chris

[lswing]

Did you do a full VCDS scan for codes? I had an error related to my CC which caused a full shutdown of the car going 90mph on the freeway, not fun. I'll have to dig it up, but it did throw a code for a control module of some sort, or throttle body control maybe...

Here's an old thread for you. http://www.rs6.com/showthread.php/23313-Cruise-control-not-working-brake-light-switch-to-blame

[lswing]

Maybe not related, my old thread. http://www.rs6.com/showthread.php/24729-Something-popped-car-shut-down-doing-85-yikes!-Cause

In Google, use "site:rs6.com cruise control" or whatever term you want to add in.

[ttboost]

Trying to recall what problem I had, that a new brake light switch fixed...but I DO recall remembering that anytime I have any kind of electrical problem, brake light switch gets replaced first. Its a switch that doesn't work like any other switch I've seen, and it's cheap and easy to replace.

[cmore]

I am working on getting my old Windows laptop fixed so I can use the vag-com to read codes. Currently, I don't have it functioning.

For the brake light switch, if there is a problem with it, should it lock out the transmission still without depressing and the brake lights still come on? I assume if the brake light switch is bad that I would notice other things outside of the cruise control.

Switch:

https://www.rockauto.com/en/moreinfo.php?pk=3021105&cc=1411401&jsn=9

[fukinavit]

Yes, starting the car without the brake pedal pushed is normal, it's when selecting drive it needs to be pressed.
Make sure the cruise stalk is pushed towards you ( I think so anyway, try it in both positions, mine didn't work and it was that) could be as simple as that.

[Aronis]

I had mine fixed (under warranty) a few years ago, March 2009.

There were no other obvious systems not working and it just ended up being the control stick was old and worn out.


Mike

[humantic]

when I got mine back in 2012 the cruise control didn't work, dealership reset the control unit and it was fine after that. cost less than $100 if i remember correctly.