78 Audi 5000 Cruise Control Warning Light Problem

I have a 78 Audi 5000 that I have had for about a month now. On two
occasions now (both when it was raining), my Cruise Control warning light
has come on. When I turn the vehicle off it stays on and will kill the
battery if I don't disconnect the battery. When the Warning light is on
anytime I step on the brakes the warning light turns off, and will do so
whether the car is running or not.

I have gone through the owner's manual and understand that the warning
light has to do with the throttle linkage being stuck or something to that
effect? And have looked for information about this and it would seem that
Audi had some problems with this during this era; however, the car isn't
sticking at all. The throttle works just fine, and the Cruise Control also
works just fine when the light isn't on. I have not had any other problems
with it at all.

What could the problem be? And if no ideas, how can I turn the light off
without disconnecting my battery? I have to wait til the car dries for it
to turn itself off.

Thanks for any help you can offer.

Ash

P.S. Any tips for finding a leak in the power steering system would also
be appreciated.

If it is like the later type 44 system, the cruise is canceled by vacuum
release switches on the brake and clutch pedals and also an electrical
signal when the brake lights come on.

I would be suspicious of the vacuum switches sticking on the brake and /
or clutch pedals. It might be simple where a spray lubricant will free
up the plastic bits.

A bit of CRC (tuner cleaner) from your local electrical parts store
might help when sprayed in the activation switch on the steering column.

Tony
'91 100q 5spd

TurboBanana wrote:
> I have a 78 Audi 5000 that I have had for about a month now. On two
> occasions now (both when it was raining), my Cruise Control warning light
> has come on. When I turn the vehicle off it stays on and will kill the
> battery if I don't disconnect the battery. When the Warning light is on
> anytime I step on the brakes the warning light turns off, and will do so
> whether the car is running or not.
>
> I have gone through the owner's manual and understand that the warning
> light has to do with the throttle linkage being stuck or something to that
> effect? And have looked for information about this and it would seem that
> Audi had some problems with this during this era; however, the car isn't
> sticking at all. The throttle works just fine, and the Cruise Control also
> works just fine when the light isn't on. I have not had any other problems
> with it at all.
>
> What could the problem be? And if no ideas, how can I turn the light off
> without disconnecting my battery? I have to wait til the car dries for it
> to turn itself off.
>
> Thanks for any help you can offer.
>
> Ash
>
> P.S. Any tips for finding a leak in the power steering system would also
> be appreciated.

Ash,
That electric system sure is an enigma, isn't it? I'll bet you don't wonder
whay Audi switched to a vacuum system mid-1980.
If you follow the wiring diagram in the Bentley Manual, you can see the
things that the warning light is connected to. In addition to the Ignition
Cut Out Relay and the Cruise Control Power Relay, the light will also come
on when (I do believe) one of the brake pressure switches on the master
cylinder is flaky - check for proper operation of these. The cruise on my
'80 seldom worked right from the time my parents had it - it would often
lose its set at random times, or the speed would decrease. When I got it,
the system was so bad that you could set it and it may work for hours, or it
may not work at all....initially....but then, an hour or so after you set it
and are cruising along, the accelerator would slam to the floor (loss of
speed signal?)....or....the car would buck uncontrollably (Ignition Cut Out
Relay or Fuel Pump Relay problem?). Eventually I just stopped using the
system altogether.
As a stop-gap measure, you could pull the warning light out and remove the
bulb.
Regarding the leak in the power steering system, you could try one of those
"magic" stop leak fluids - as the system uses ATF-type fluid and not the
synthetic "Liquid Gold" fluid (aka "Pentosin" or "Goo2000"). If the leak is
not stopped by that, look up a rebuilder in your area.
Cheers!
Steve Sears
1987 Audi 5kTQ - Pneumatic Cruise - working well
1980 Audi 5k - Electric Cruise - not working
1962 and '64 Auto Union DKW Junior deLuxes - Organic Cruise (foot) - works.
(SPAM Blocker NOTE: Remove SHOES to reply)

"TurboBanana" > wrote in message
news:%%urc.557890$oR5.300166@pd7tw3no...
> I have a 78 Audi 5000 that I have had for about a month now. On two
> occasions now (both when it was raining), my Cruise Control warning light
> has come on. When I turn the vehicle off it stays on and will kill the
> battery if I don't disconnect the battery. When the Warning light is on
> anytime I step on the brakes the warning light turns off, and will do so
> whether the car is running or not.
>
> I have gone through the owner's manual and understand that the warning
> light has to do with the throttle linkage being stuck or something to that
> effect? And have looked for information about this and it would seem that
> Audi had some problems with this during this era; however, the car isn't
> sticking at all. The throttle works just fine, and the Cruise Control
also
> works just fine when the light isn't on. I have not had any other
problems
> with it at all.
>
> What could the problem be? And if no ideas, how can I turn the light off
> without disconnecting my battery? I have to wait til the car dries for it
> to turn itself off.
>
> Thanks for any help you can offer.
>
> Ash
>
> P.S. Any tips for finding a leak in the power steering system would also
> be appreciated.