[V8] Cruise Control In-op: '90 V8

Buchholz, Steven Steven.Buchholz at kla-tencor.com
Tue Aug 16 13:14:07 EDT 2005

... well, there are no less than three "tidbits" on the topic under the
V8 Model in the Audifans KB ... which also include a link to Huw
Powell's CC troubleshooting page.  

My first suggestion would be to pull the vacuum line off the pump and
verify that if you apply a vacuum the throttle motor pulls in and stays.
If you don't have a vacuum pump you can manually compress the vacuum
actuator and then seal off the vacuum line and confirm that the vacuum
actuator doesn't move.  

The next most common issue is the electrical switches ... you have
verified that the vacuum part of the brake switch works ... did you test
the electrical part?  

Finally, if all that stuff doesn't cure the problem it is a more
difficult problem.  Perhaps the speed signal isn't making it to the
controller ... is the speedo of the car working well?  On #344 I found
the CC inop problem to be due to a faulty control switch on the stalk

Steve B
San Jose, CA (USA)
>         I've got my '90 V8 sold, and the deal ready to close with one
> notable caveat: the cruise control must be made to function.  First of
> I don't know when/if it ever worked previous to my ownership....  I
> to the first most likely cause and found indeed the vaccuum switch on
> brake not holding.  Took it apart and cleaned everything and then
> re-assembled, now it holds vaccuum just fine when the brake pedal is
> rest.
>         I've printed the multi-page electrical diagnostic which I
> I'll need to go through; but just checking to see if there's any other
> super-basic "go here first" items.  Reply to: rob at rallydogracing.com

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