[s-cars] Hi beams with fog

Thu Jun 12 23:13:48 EDT 2003

Nope, the fog light switch isn't relayed in the way you are thinking,
Vincent. The full power to the fog lights always flows through the switch,
the relay just interrupts the power to the fog light switch when the high
beams are switched on. A cursory examination of the Bentley wiring diagram
will show you how the wiring is configured.

You are right, of course, my fog light switch is mine, but in this case I
don't have to worry about burning it up any faster without the relay!

Fred

-----Original Message-----
From: Vincent Fregeac [mailto:vfregeac at sympatico.ca]
Sent: June 11, 2003 10:21 PM
To: 'Fred Munro'; 'Aaron'; 'Audi - Scars'
Subject: RE : RE : [s-cars] Hi beams with fog

Fred,

Aren't you unrelaying a switch this way. Audi already planned
obsolescence on many light switch I don't think we need to add another
one to the list! But, after all, the fog light switch on your car is
yours.

Vincent
'96 //S6 with relayed switch.

-----Message d'origine-----
De : Fred Munro [mailto:munrof at sympatico.ca]
Envoyé : 10 juin 2003 21:10
À : Vincent Fregeac; 'Aaron'; 'Audi - Scars'
Objet : RE: RE : [s-cars] Hi beams with fog

I've come up with an easier quick fix - remove the fog light relay (J5)
and
jumper terminals 87 and 30 in the relay socket. The fog lights will now
come
on whenever the switch is activated. Make your jumper heavy enough to
carry
the current ( 12 or 14 gauge wire should be OK, male spade terminals on
both
ends, slide the jumper terminals into the female terminals in the relay
socket).

Five minute job, including jumper fabrication.

HTH

Fred Munro
'94 S4

-----Original Message-----
From: s-car-list-admin at audifans.com
[mailto:s-car-list-admin at audifans.com]On Behalf Of Vincent Fregeac
Sent: June 9, 2003 9:54 PM
To: 'Aaron'; 'Audi - Scars'
Subject: RE : [s-cars] Hi beams with fog

Aaron,

The mods is detailled below, courtesy of Fred Munro originally. Quick
summary: terminal 85 on relay J5 to the ground.

Vincent.
___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.

-----Message d'origine-----
De : s-car-list-admin at audifans.com
[mailto:s-car-list-admin at audifans.com] De la part de Aaron
Envoyé : 9 juin 2003 14:27
À : Audi - Scars
Objet : [s-cars] Hi beams with fog

Im sure I saw something about mods to be able to keep fog lights on when
in high beam mode.
Any recollections?
Thanks
Aaron

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