[s-cars] How does it know your headlight ain't on?

[Taka Mizutani]

I would kill the bulb check myself- I don't need the car to tell me that my
lights are out- simple pre-trip by checking the lights in the garage with
the door closed is easy enough- only ones I'd miss would be the license
plate bulbs and the front marker lights.

My Volvo has the same setup- tells me the light is out, but it's a little
more advanced- it can actually tell me which bulb is out, just not on which
side.

Taka


On Mon, Sep 20, 2010 at 8:32 PM, JC <jc at j2c3.com> wrote:

> Stupid bulb check.  I think all the Audi units are roughly the same... But
> it's not just headlights at all, covers turns and brakes too. AFAICFO its
> resistance and/or current sensing. Once wiring gets wanked a little it seems
> hard to correct. Been told it can even happen from different brand bulbs on
> left vs right kind of stuff.  Or from wiring/ground deterioration on old
> cars. BTDT with famous hatch rewiring. Bulb check started going
> intermittently, which led me to find the classic hatch wire disaster. OK
> great i say and fix my hatch mess. However now everything on my car seems
> 100% fine but the "No Christmas tree ornament alert" as my wife calls it,
> would still light. I even tried complicated DMM checking of extensive crap
> including voltage at the sockets, resistance to ground at every socket, etc.
> Finally in exasperated irritation from having to deal with the constant
> BEEEEP of the thing going on/off I got pissed and neutered the bulbcheck
> relay. One thing I never got to try was a new relay, my bud w a C4 A6 is
> fine for me to steal his for a test but I always have too many beers before
> we get around to it and forget to actually grab it.
>
> So far only a useless story for you, except to try checking voltages
> Someone here or on QW recently had luck w replacing the relay IIRC?
>
> __________________________
> John Cunningham
>
> US Mobile +1 (617) 750-5025
> China +86(0)136 6080 9560
>
> Sent from iPad
>
> On Sep 21, 2010, at 3:42, David Kase <dbkase at gmail.com> wrote:
>
> > Patient is a B5 S4.  I get the headlight-is-out warning (I assume it is
> just
> > detecting the headlights) but the headlight works.  The light was out and
> I
> > found that the wire from the wheel well area into the cabin was bad.  I
> > replaced the wire with a slightly different routing and the warning is
> still
> > on.  Did I maybe bypass a component that would let the system know that
> > juice is flowing to the light?  Or?
> >
> > Kase
> > prepping B5 S4 FS
> > _______________________________________________
> > S-CAR-List mailing list
> > http://audifans.com/mailman/listinfo/s-car-list
> > http://www.audifans.com/kb/List_information
> _______________________________________________
> S-CAR-List mailing list
> http://audifans.com/mailman/listinfo/s-car-list
> http://www.audifans.com/kb/List_information
>