Cruise control not working

[adjuster]

UPDATE: Went for a 20 mile drive, "massaging" the switches for both resume/set/on/off and it finally, at the end of the 20 miles, started to work!

Nice advice, I'd have cursed the dang thing for awhile longer, and replaced the switches eventually.

This "free" repair is much better all around.

Thanks for the advice.

I think this S8 sat around quite a bit, as the mileage is pretty low with less than 75,000 miles on it.

[HPsauce]

Originally Posted by Zip

Would be very interested to see how you get the stalk apart

Me too, does anyone know how to replace or dismantle it?

Mine has started seriously playing up again. The other day it did work eventually after some "abuse" of the switches, but yesterday it just wasn't playing at all.

Also, does anyone know if there are any codes that might show up as a fault.

Mine is the PF version, so you do indeed feel the earth move (under the accelerator).

[Night Train]

I'd suggest squirting some switch cleaner/ lubricant around/ into the offending areas then vigourously working the switches.....
Be careful not to spray all over the interior though, so hold a cloth/ rag around the stalk...

[HPsauce]

Well, as noted briefly in another thread, I've doused it in Isopropanol several times and worked the switches "vigorously". Nothing mucky came out though.
Been on a short slow test drive - about 20 minutes at 30/40mph - and it still wasn't working despite trying every few yards.

Then just short of home it suddenly engaged; I have no idea what was different. Just enough time to check that the increase speed switch worked before having to brake and turn off down my road.
(no opportunity to continue and test further due to roadworks with traffic lights)

So, none the wiser really.

However, looking closely at the switch it appears that it "might" be possible to prise it open in situ without taking the stalk off (airbag out job methinks ) - anyone ever tried that or know if it's possible?

[David's8]

I had problems when I got my S8 in January. The issues boiled down to 2. Firstly, underuse made the switch temperamental and, secondly, my right foot. If I left my foot on the throttle for a nanosecond after pressing the CC engage switch it would not engage. The trick was to ensure you lifted your foot off in the nanosecond before you engaged.

The removal route is well covered in Audi pages (as you probably know):

http://www.audipages.com/Tech_Articl...chreplace.html

[HPsauce]

Ah, thanks for that useful "how to" link.
Mine's a late 98 so I do need to check the revision carefully!

As for "foot off first" I do that automatically, but I have found in the past that it wasn't strictly necessary.

[HPsauce]

Is there any way to tell, without dismantling, whether you have a RevC or RevN cruise stalk?
Looking at the AudiPages photo the cloth-wrapped cable seems to leave the back of the stalk in a different direction...
Down, forwards, up and across on C.
Up, forwards, down and across on N.

Edit: I can see mine leaves the back of the stalk, goes up, round a plastic lug and towards the driver, then down the drivers face of the stalk back and across into the cowling.
So, I guess it's an "N".......

[HPsauce]

Well, I just went for a short drive and it's working perfectly!

Maybe it's due to all the cleaning and abuse I applied to the switch the other day.
Or maybe it's because I was very careful to "flex" the throttle and ensure it was completely released and I could feel speed dropping before pressing the engage button?

Anyway back to being a relatively happy bunny.
(just have the gearbox to really worry about now...... )

[B@fink]

Mine (97 pf) stopped working last summer, worked ok and then after 10 mins would suddenly drop and no longer engage. Continued to do that for a week or 2 with me assuming the switch was being a bit iffy before packing in completely. No codes set (because as I discovered it just thinks it's turned off!) and all the mechanicals seemed to be fine. Long story short after a bit of internet research for cruise control problems turns out the controller (like the type fitted to mine) dies...... controller swapped and tada! cruise works first time everytime. There was a "how to" on taking that type of controller to pieces resoldering the dodgy connections (3 bits of the electronic dodads attached to the pcb break their solder joint and drop dead) to bring them back to life but frankly whilst I can wave a spanner if needs be, electronic whizz bangs are not my thing! Don't always assume the switch is the cause!!!

[HPsauce]

Where is the controller, easy to get out?
I don't mind taking electronics apart and resoldering etc. at all.
I've got the "old school" vacuum servo cruise which I presume is basically the same as yours, so if it plays up again I'd probably want to have a look at it.

Ah, think I've found it, behind the glovebox according to this thread:
http://forums.audiworld.com/showthread.php?t=2758040

The actual module 4D0907305 seems to be common to several Audi models, not just the A8.