quattro digest, Vol 1 #4595 - Headlight relays, WTF!

[Larry C Leung]

N-BTDT with respect to the controller (none on my '89 - 200), but....

If this is the normal correct controller function for the A6, you can
build a resistance
bridge (this is signal level current, so it wouldn't require anything
special in
the way of resistors) to lower the "off" position voltage below the
trigger threshold.

I'd build the bridge with soldered resistors, with a 15V or better
rating, I'd suggest
at least 1/4 watt (pretty standard) although you're not loading them that
high. Pick
ANY two resistors in a ratio that you'd like to drop the voltage to.

Example. Assume system is 12V (it's really 13.5V)  and the minimum
reliable trigger
voltage is 8V (yes, we know, you've measured 7.5V to trigger, but as
things heat up,
this may drop below threshold). You need a ratio of 2/3 to get 12V to 8
V,

i.e.         12V * 2/3 = 8V

So, you buy say a 20ohm and a 30 ohm resistor for your bridge. Note, for
this job,
you may be able to get away with the really cheap 20% resistors (i.e.
measured is
within +/- 20% the rating of the resistor) as relays are not precision
electronic devices
that need specific voltages.

You wire the 30 ohm resistor to ground, solder the 20 ohm resistor to the
other end
of the 30 ohm job, and then wire the remaining lead to 12V + relay signal
lead that
formally went directly to the relay trigger. The relay trigger lead then
goes to the
junction of the 20 and 30 ohm resistors.

Note, NOW the leak voltage will also drop by the same 2/3 ratio, so for
your
"current" input of 7.5 V "leakage" you will now get:

7.5V * 20/30 = 5V.

Hopefully, this will drop the voltage below the High Beam relay trigger
voltage.

Now, some may be concerned about the leakage current going through the
relay.
Yes, it will heat it. And no, it won't be of major concern, considering
that unless
you have a latching relay (usually only in solid state circuits), the
normal relay
is used to having 12V on it for as long as the headlights are on. This
MAY eventually,
cause winding insulation breakdown in the relay coil, but I rather doubt
it.

Now, you may have to adjust the ratios of the resistors to suit the
minimum trigger
voltage of your relays. Remember, the greater the difference of the
resistances, the
greater the ratio, and the greater the drop of the trigger voltage. The
second resistance
value would be the one that attaches to ground.

Assuming input voltage is 12V

Examples:                 20/30 ohms                Trigger Voltage is
2/3 the original or 8V

                                20/20 ohms                Trigger Voltage
is 1/2 the orignal or 6V

                                30/20 ohms                Trigger Voltage
is 1/3 the original or 4V

etc.

HTH!

LL - NY a.k.a. the Physics Teacher (getting prepped to teach the circuits
unit)


> From: "S J & I Santoliquido" <santoliquido at cox.net>
> To: "Quatro list" <quattro at audifans.com>
> Subject: Update: Relayed lights. Highbeams stay on. WTH?
> Date: Tue, 11 Feb 2003 18:42:02 -0500
>
> O.K. When we last saw our hero he was struggling to understand why,
> after
> relaying the headlights on his A6, his high beams would, once being
> turned
> on, not go out until all the headlights were shut off.
>
> Now after several suggestions from fans, some of them quite useful,
> we have
> more information.
> The high beam relay triggering voltage, formerly known as power to
> the high
> beams, is not measuring 0vdc when the high beams are off and low
> beams on.
> It is measuring 7.5 vdc with the relay removed (open circuit), and
> 4.2vdc
> with the relay installed (under load). When the headlights (high and
> low)
> are off, it measures 0vdc, with 0 ohms resistance to ground (relay
> removed),
> as expected. With Headlights on, and high beams turned on, it
> measures
> battery voltage, ~12vdc.
>
> So; I believe that the headlight control unit (that double relay
> looking
> thing on the aux relay panel) is bleeding enough current to the high
> beam
> line to maintain the relay latched, but not enough to latch it.
>
> The question is; is it a bad controller? Or is this normal behavior
> for this
> controller, which requires some type of work-around?
>
> Any thoughts gladly parsed.
>
> TIA
> Steve
>
>
>
> --__--__--
>
> Message: 13
> Date: Tue, 11 Feb 2003 15:55:10 -0800
> Subject: Tickets and tuition and money... Oh my!
> From: Benjamin Kaupp <bkaupp at ugconnection.com>
> To: quattro at audifans.com
>
> Hey folks... I'm not sure if this is gonna happen, but it is
> looking
> more and more like a possibility that I will need to sell my baby.
> I'm not putting her up for sale yet, but merely polling the list to
> see
> what a fair price would be.
> It's an '87 4kcsq with the leopard leather (tan and black). I would
> give the interior an 8.5 or 9. The leather is nearly perfect, and
> everything but the oil temp gauge works.
> Mechanically it has new front suspension, new front brakes and
> wheel
> bearings (sitting in my garage, but easily installed), 5000 miles
> on
> the Bridgestone Potenza RE950s (great tires) all round, and a
> recent
> full tuneup. The paint is still beautiful with the exception of a
> large
> blemish (bad respray?) on the front right fender and your usual
> sundry
> dents and dings for a fifteen year old car. From fifteen feet away,
> the
> Alpine white paint looks spotless, and it's perfectly presentable
> from
> close distance as well.
> Problems include:
> it needs new rear shocks and bushings something fierce
> the throttle can't be touched for the first minute or two the first
> time you start it up, but that went away when I drove it more than
> twice a week
> the valve cover gasket is leaking tiny amounts of oil into the fan
> blades, which makes the engine compartment filthy and stinky
> the right rear taillight is leaky and nonfunctional (brake lights
> work
> still)
> The odometer stopped working at 157,000 miles, but I have kept
> rough
> estimates of distance since and we only have around 3500 miles
> since
> (1000 of them last weekend)
>
> Of course, the sound system o' doom is a negotiable addition to the
> car, or I could just throw in some of my old Blau speakers
>
> It's a great car, and I hate to see it go, but I'm looking at losing
> my
> license and potential for jail time (unlikely, but the threat
> exists)
> and I don't want to leave her sitting for six months. Add to that
> new
> financial burdens and something slightly more reliable and slightly
> cheaper to run is tempting (at least until I can afford that UrS4).
> Once again, I am not looking to sell the car just yet... just
> looking
> for what's a fair price in Northern California.
>
> TIA
> -Ben Kaupp
> '87 4kcsq (but for how long)
> coming soon - narrowed down to a 240z (thanks Rob), a Miata, a 510,
> and
> an RX-7 convertible (did I say cheap? oops)
>
>
> --__--__--
>
> Message: 14
> From: Kwattro at aol.com
> Date: Tue, 11 Feb 2003 20:48:22 EST
> Subject: Re: ITB CGT FAQs
> To: sfisher71 at yahoo.com
> Cc: quattro at audifans.com
>
> --
> [ Picked text/plain from multipart/alternative ]
> In a message dated 2/11/03 5:37:32 PM Eastern Standard Time,
> sfisher71 at yahoo.com writes:
>
>
> > 1 - I'm pretty sure a few people here run CGTs as
> > track cars, if not in ITB then in some other venue
> > (marque club track days, etc.)  What kinds of things
> > have you found to work for you, and what was a waste
> > of time and/or money?
> >
> > 2 - Since suspension seems to be the main area of
> > modification, what brands of spring and shock are
> > available for the CGT, and what kind of experience
> > have listers had with them?  I know this car isn't
> > quite as popular as a watercooled VW, where there are
> > dozens of brands from scores of vendors, but BTDTs
> > with specific vendors will be very much appreciated.
> >
> >
>
>
>
> I run my GT on the track, and have had a lot of success making the
> car run
> similar lap times to M3's and the like.  I run Ground Control
> coilovers with
> 380/410 progressive rate front springs, and 300lb rear springs.  I
> run Koni
> sports set all the way hard, a Jamex stress bar, Suspension
> techniques sways
> (30mm ft, 27mm rear).   I also run 15x7's with 225-50-15 Goodyear
> GS-CS's,
> although I'm going to run 225-45-15 Hoosier R309's this year.  The
> car is
> very quick, with a milled head and tubular header with 2.5 inch
> exhaust.  I
> pulled the AC and swaped the stock seats out for Kirkey race seats,
> and have
> a 4 point cage.  I'm able to run the car in current trim within 2
> seconds of
> the record ITB times at Limerock - something that I've been very
> happy with.
> The car is heavy comparied to ITB, and I think with the fresh
> Hoosier rubber
> I can run around 1 second shy.  I think that the stock brakes are
> fine in the
> car (I have an 86, with the upgraded 10.1 rotors, although you might
> be able
> to run either scirroco 16v 10 or corrado 11 inch brakes), and I run
> Pagid
> pads with Ate powerdiscs - slotted rotors.  I think with a touch
> more rear
> spring, the car would rotate more, but you really have to be able to
> drive
> the car on the edge, and forget it if it rains :-)
> If you can run them, get a set of Hoosier dirt stockers for rain -
> you won't
> regret it.  I recently lapped a 996 Twin Turbo (420+hp, awd) in the
> rain on
> them - but you can't run them in the dry.  The GS-CS's are supposed
> to be
> worth an extra second, but mine are old, and they don't last as long
> as
> hoosiers.  I don't think you'll need an oil cooler or additional
> radiator
> cooling - I haven't had any problems, even running at high altitude
> at high
> temps (Walkins Glen in June).  If you can afford it, put in the
> heavier rear
> springs and get the Quaife diff.  I'm planning on upping horses
> soon, but for
> a budget the car can't be beat - less than the downpayment on an M3,
> and they
> can't catch me :-)...well, on a long straight...
>
> Later!
> Carter
>
> --__--__--
>
> Message: 15
> Date: Tue, 11 Feb 2003 21:04:04 -0500
> To: Tom Leppke-Hennig <printhead at usinternet.com>,
>         quattro at audifans.com
> From: Brett Dikeman <brett at cloud9.net>
> Subject: Re: 1.8t vvt?
>
> At 5:15 PM -0500 2/11/03, Tom Leppke-Hennig wrote:
> >Can anybody help settle a friendly dabate I have going with a
> friend? We
> >are wondering if a 1.8t motor has variable valve timing. I say it
> >doesn't, he says it does.
> >
> >Anybody out there have the straight dope?
>
> They've been doing it on the V6 for years(more complexity as time
> goes on, and variable intake geometry to boot at some point as
> well).
> I believe the 1.8t only recently gained both technologies; not sure
> when, but it might have come with the new redesigned A4.  Tech
> specs
> I found quickly for the '99 model showed no variable nothin' on the
> 1.8t.
>
> I saw the 5-valve V6 head on a display stand a while back; it's a
> remarkably simple system- it has two sliders on the top+bottom of
> the
> timing chain, and it moves the assembly to transfer the slack in
> the
> chain, changing the driven cam's position relative to the other.
> You
> can push the piston up or down and actually see the other cam shift
> slightly.
>
> What's also interesting is how the 3rd valve in the 5-valve head is
> at a different angle, which makes for an interesting cam lobe
> setup...has a different profile to make it operate in concert with
> the other two.
>
> Brett
> --
> ----
> "They that give up essential liberty to obtain temporary
> safety deserve neither liberty nor safety." - Ben Franklin
> http://www.users.cloud9.net/~brett/
> http://www.apple.com/switch/
>
> --__--__--
>
> Message: 16
> From: "Jennifer Toppin" <toppin465 at charter.net>
> To: <quattro at audifans.com>
> Subject: 200 Q Parking Light problem
> Date: Tue, 11 Feb 2003 21:44:00 -0500
>
> This is a multi-part message in MIME format.
> --
> --
> [ Picked text/plain from multipart/alternative ]
> GlacierHello Mother List,
>
> A friend of mine has a 1989 200 Q with the MC engine.  Tonite the
> parking lights, tail lights & instrument cluster decided they didn't
> want to go out.  Has anybody else had this problem?
>
> Thanks for Your Help!
>
>
>
> Dave Toppin
>
> --
> [ Glacier Bkgrd.jpg of type image/jpeg deleted ]
> --
>
>
> --__--__--
>
> Message: 17
> From: "Chander Balakrishnan" <balakrishnan3 at attbi.com>
> To: "Quattro List" <quattro at audifans.com>
> Cc: "Chander BP BP" <balakrc at bp.com>
> Subject: 2000 A6 Oil Warning light LONG)
> Date: Tue, 11 Feb 2003 22:14:36 -0600
>
> This is a multi-part message in MIME format.
> --
> Fellow listers:  My boss bought a new Audi A6 about 2 + years ago.
> He
> purchased it partly based on my wonderful experience with my 1987
> 5kcsq
> sedan and 1990 200 tqw.  Recently the Oil warning light has been
> acting up
> in his car.  The car has 48k miles on it (his wife drives it to the
> college
> where she teaches, about 65 miles roundtrip every day).
>
> Now here are the symptoms:  The car behaves just fine until the
> engine is
> fully warmed up, and when the car speed goes down (like coming off a
> highway
> and driving on city streets) the Oil warning light comes on (the
> light with
> the oil can picture on it) along with a very loud buzzer that can
> scare most
> people.  It goes off after the car has been running at the lower
> speed for a
> little while.  But yesterday, it did not go off for a few minutes.
>
> The car does not have an oil pressure gauge, and the oil temperature
> reading
> is normal.  Audi said that the pressure sensor was the likely
> culprit, and
> have changed it twice.  Today they called him and told him that when
> they
> took the pan off, they discovered that an o-ring was bad in the oil
> pumping
> system and have replaced it.  The problem now seems to have gone
> away.
>
> My boss's concern is that the engine might have suffered some damage
> due to
> lack of oil in the past when the light came on, and that the problem
> might
> manifest itself 20k or more miles later when there is no warranty
> protection
> for the car.  My own sense is that Audi engines are usually over
> designed
> and that he should not be concerned about damage to his car's
> engine.  I
> would appreciate comments from anyone who might had a similar
> experience
> with their car.  Thanks.
>
> Chander
> 1987 Audi 5kcsq SJM
> 1988 Jetta
> 1990 Audi 200 TQW
> 2003 Jetta TDI wagon
>
>
>
> --
> [ winmail.dat of type application/ms-tnef deleted ]
> --
>
>
>
> --__--__--
>
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