[s-cars] Eurolight problem

Sun Mar 9 11:36:46 EST 2003

Hi Bob;

The low beam is supposed to be on when the high beam is on.

As for the high beam latching problem (search for "latching" in the
archives), I ran into this problem a couple of years ago and figured out the
cause and cure for the Canadian S-cars. I think the U.S. cars may have
slightly different wiring around the foglight system, but I don't know for
sure.

On the Canadian cars, the problem is with Audi's foglight wiring system.
They wanted the fog lights to turn off when the high beams were turned on,
so they cleverly grounded the fog light relay through the high beam bulbs.
Turn on the high beams, power to the bulbs, +12 volts instead of ground to
the fog relay, the relay opens, fog lights turn off. Quite clever, really,
until Euros are fitted with relays of their own. Now the fog light relay is
grounded through the high beam relay coils instead of the bulbs (as per
Blau's harness). When you activate the high beams, the high beam relay
closes and the high beams come on. When you try to switch off the high
beams, enough current passes back through the fog light relay coil to keep
the high beam relays latched closed and the high beams stay on. These relays
usually drop out below 5 volts, anything above that will keep them latched
shut. Try pulling the fog light relay out - if the high beams work properly,
this is your problem.

I doubt that Blau knows about the problem or if they do, how to fix it. I
bought my Euros from PGPerformance, and they knew about the problem but
didn't know how to fix it until I managed to figure out and fix my own
lights. Some listers have said the U.S. cars have different wiring, so this
may or may not apply to your car, Bob, but try pulling the fog relay to
check it out.

Some listers have reported that using different relays, presumably with
different drop-out voltages, fixed the problem.

I have attached a post I originally put out in 2000 detailing the problem
and the fixes. I have the "cheap Fix" in place and have wired the left
headlight for the "Proper Fix", but I kind of like the "Cheap Fix" because I
can use the fogs whenever I want!

HTH

Fred Munro
'94 S4 (Euros, HID, no latching problem!)

___ATTACHMENT____

    I've gone through the Bentley wiring diagram, tested the system on my S4
and think I've found the problem causing the high beam relays to latch on.
I've come up with a couple of fixes, but haven't field tested them yet -
thought I'd throw this out to the list for info and comment.

PROBLEM:
    When the stock high beam wiring is used to drive a pair of relays for
Eurolights on the UrS4, the relays will activate when high beam is first
selected and will remain on when low beam is selected. The relays will open
if the headlights are switched off, the fog light relay is removed, or the
stock wiring is removed from one relay and reconnected to one high beam
bulb.

CAUSE:
    The AE (Audi Engineers) have decreed that the fog lights will shut off
when high beams are selected. This is probably due to some obscure safety
legislation or concern about heat in the headlamp housing with 3 bulbs
illuminated. Since the S4 low beams are always on, even when high beams are
selected, the standard dimmer switch cannot be used to trip out J5, the fog
light relay . AE have come up with a rather elegant solution - the coil on
J5 (terminal 85) is grounded through the high beam bulbs. When the high
beams are switched on, terminal 85 gets 12 volts, the same as terminal 86 on
the other side of the coil, and the relay drops out, shutting off the fog
lights. Terminal 86 is only fed power when the headlight switch is fully on.
    Along comes a FAE (Feckless Audi Enthusiast) who installs a set of
Eurolights and relays the high beams to the alternator to get maximum
voltage, maximum lumens, and avoid frying the headlight switches with the
500w "off-road" bulbs he's installed. The stock high beam wiring is used to
trigger the relay coils in time honoured fashion. When the headlights are
turned on with low beam selected, all is well - the fogs work and the low
beams work. High beam is selected, and the relays activate, turning on the
high beams and temporarily blinding the FAE with reflection off the garage
walls. Low beam is selected but the high beams stay on. Once the FAE becomes
aware this is not an image burned into his retinas, he finds it is because
the relay J5 coil is now grounded through the high beam relay coils and is
passing enough current to keep the high beam relays closed. Pulling the J5
relay or shutting off the headlights interrupts the power flow and lets the
high beam relays open. Reconnecting the stock high beam wiring to one bulb
grounds J5 through the lower resistance of the bulb and allows one high beam
relay to work properly.

FIX(es):

    I've come up with two fixes, one which retains the current system
functionality and a cheaper, easier one which doesn't.
    The "Cheap Fix" is to remove the female terminal 85 from the relay J5
socket and insulate it with a piece of shrink tubing. Install another female
terminal into the socket and run it to ground. This will give you fog lights
whenever the headlight switch is "on", even when high beam is selected. You,
the aware and in-control Audi driver, will have to remember to turn them off
when you flip on the highs. Since high beams are not too useful in fog, this
may not be a great hardship.
	The "Proper Fix" is to take the wire mentioned above and rather than run it
to ground, run it to terminal 87 on one of the high beam relays. This will
bypass the relay and ground the Fog Light relay through the high beam bulb
filament, restoring the original system functionality.

-----Original Message-----
From: s-car-list-admin at audifans.com
[mailto:s-car-list-admin at audifans.com]On Behalf Of Robert Myers
Sent: March 8, 2003 2:53 PM
To: s-car-list at audifans.com
Subject: [s-cars] Eurolight problem

--
[ Picked text/plain from multipart/alternative ]
Hi Y'all,

This has probably been discussed before but...

Just installed the Blau wiring harness for the new Eurolights.  I did not
modify anything (yet) in their harness.

The low beams turn on when they are supposed to turn on.  Main switch on
and dimmer switch in low beam position.

Flip dimmer switch to high beam position and high beams come on.  So far so
good.  The low beams stay on when the high beams turn on.  This strikes me
as probably not correct but I wouldn't mind if these lights operated this
way normally.

Flip dimmer switch back to low beam position and both the high beams and
the low beams stay on.  OOOOps!  To turn high beams off and go back to low
beams I must turn the main switch off and then back on with the dimmer
switch in the low beam position.

What is the solution?  I would have thought that Blau would have had this
problem already ironed out before selling their harness.

____

Peace Takes Brains.

Bob
*****
  Robert L. Myers 304-574-2372
  Rt. 4, Box 57, Fayetteville, WV 25840 USA WV tag Q SHIP
  '95 urS6 Cashmere Grey - der Wunderwagen ICQ 22170244
  http://www.cob-net.org/church/pvcob.htm
*****
--

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