90q No Brake Lights

Mark R speedracer.mark at gmail.com
Mon Mar 12 16:38:21 EDT 2007

I thought just the opposite.. the early systems didn't monitor the head
lights.  But I could very well be mistaken.

I also recall the early autocheck systems could be fooled by both bulbs
equally out, but later systems actually referenced the delta between
resistance AND checked to make sure there is SOME current flowing.  Then
again, I could be completely wrong in my recollection.

I have run into situation where I've replaced one bulb and the autocheck
still shows a problem.  Probably due to corrosion, different elements, etc.
Cleaning the sockets, verifying ground, and replacing both bulbs solved the
problem.  Replacing both bulbs was the key (tried that last).

Then again, black electrical tape can be used to mask the autocheck
illumination.   =)

Mark Rosenkrantz

On 3/12/07, Huw Powell <audi at humanspeakers.com> wrote:
> > If both bulbs are out, and the autocheck system doesn't detect a
> difference,
> > would it signal a failure?
> No, although in the case of headlights, you'd probably notice.
> I didn't think the autocheck in the type 89 even paid attention to the
> brake lights, I thought it was just on the headlights...
> > I understood the autocheck system measures the different between the
> > left/right bulbs and signals a failure if it detects a difference.
> --
> Huw Powell

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