HIDs with relay

vtlew · 01-13-2006, 09:06 PM

I installed HIDs in my '94 S4 and they are awesome. After reading up on things I decided to add in a relay to preserve my headlight switch. They work great but now the auto-check system thinks my headlight bulb is out. Every time I turn on my headlights I get the defective headlight warning symbol. Does anyone know how I can prevent this? Wire in a resistor, perhaps? I did STFA and didn't find anything. Thanks.

repeater · 01-13-2006, 09:08 PM

My car has had three different HID systems on it for over 5 years and I have never seen the headlight bulb thing, although I've heard about it on newer Audis. Not sure whether the previous owner might have done something before I had it. As far as I can see though, there are no relays anywhere for my headlights added in, and I've been through the wiring.

El Desamparado · 01-13-2006, 09:14 PM

vtlew · 01-13-2006, 09:17 PM

quattro20v · 01-13-2006, 09:25 PM

required resistance (it is lower now that you have relayed it).

There is a way to modify the circuit board inside the LCM (which is located in the relay box under the hood) to "fooling" the auto-check.

If I can locate the write-up, I'll post it.

vtlew · 01-13-2006, 09:29 PM

am I missing something?

quattro20v · 01-13-2006, 09:33 PM

from urs4.com

Phase 3: Lobotomize the autocheck lamp warning module

For the auto enthusiast who can't discern that a headlight has burned out, Audi has thoughtfully equipped the car with a warning system that beeps and displays a yellow X-ed out bulb in the autocheck display. The lamp warning module on the UrS4 is a complex piece of kit located in the main relay box in the plenum under the hood. It also warns for burnt out taillights and brake lights, which is a useful feature. The headlight warning circuit consists of two precision resistors and an IC which compares microcurrents across the headlight bulb filaments. Since the ballasts have a
different resistance than H1 bulb filaments, the autocheck will drive you to distraction unless you make like a neurosurgeon and lobotomize the thing. The procedure I used is based on Igor Kessel's excellent post in the Headlights section of urs4.com, here. Don your scrubbies, wash up, and let's begin.

1. Remove the lamp warning module and gurney it to the operating table. It looks like a double-wide relay and is located in the main relay box under the hood.

2. Remove the cover from the module. Locate the precision resistors for the headlight comparator (Photo L1).

The terminals for the headlights are tagged 56bl, 56bl1, 56br, 56br1. It is easy to locate them by turning over the board and following the foil traces from the resistor joints.

3. Flip the board over and locate the solder joints for the resistors and the terminals connected to the resistors. We are going to short out each resistor by soldering together the terminal joints at the bottom of the board and isolate the resistors from the IC by cutting the foil traces on the board with a scalpel (or reasonable facsimile - I used an Olfa knife). You may want to cut the traces in an area which makes it easy to re-join them in case you want to restore the autocheck operation when you reach your dotage. Photo L2 shows the board with the modifications complete. Make sure the traces are well cut or the autocheck will still activate, usually on bumpy roads.

4. Reassemble the module, insert it in the car, and test. Blessed silence! The operation is a success! The patient is blissfully unaware of the Frankenlamps lurking under the hood! Bwaaahahahahaah!!

5. Enjoy your new high-tech lights

quattro20v · 01-13-2006, 09:35 PM

http://web.archive.org/web/*/http://www.urs4.com

El Desamparado · 01-14-2006, 12:58 AM

4Driver4 · 01-14-2006, 04:33 AM

That's the only reason I can see for adding relays.

01-13-2006, 09:06 PM	#1
vtlew Member Account #: 81274 Join Date: Sep 2004 Posts: 356	HIDs with relay I installed HIDs in my '94 S4 and they are awesome. After reading up on things I decided to add in a relay to preserve my headlight switch. They work great but now the auto-check system thinks my headlight bulb is out. Every time I turn on my headlights I get the defective headlight warning symbol. Does anyone know how I can prevent this? Wire in a resistor, perhaps? I did STFA and didn't find anything. Thanks.

01-13-2006, 09:08 PM	#2
repeater AudiWorld Super User Account #: 56100 Join Date: May 2003 Posts: 13,845	Hmmm... My car has had three different HID systems on it for over 5 years and I have never seen the headlight bulb thing, although I've heard about it on newer Audis. Not sure whether the previous owner might have done something before I had it. As far as I can see though, there are no relays anywhere for my headlights added in, and I've been through the wiring. __________________ Tim - Holland, MI I don't own an Audi no more...Why am I here? I don't know. 06.Honda Ridgeline - my anti-Audi 04.Mini Cooper (hers) 94.UrS4 - with stuff (sold..sniff) 99.A6Aq - (sold) 88.80 - The Duke (sold)

01-13-2006, 09:14 PM	#3
El Desamparado Junior Member Account #: 81086 Join Date: Sep 2004 Posts: 993	take a look at urs4.com "technical" there should be a write up on it in there somewhere. __________________ 95.5 S6 (sold) 86' 4000CSQ (sold)

01-13-2006, 09:17 PM	#4
vtlew Member Account #: 81274 Join Date: Sep 2004 Posts: 356	warning light only came on after I added the relay

01-13-2006, 09:25 PM	#5
quattro20v AudiWorld Super User Account #: 52091 Join Date: Feb 2003 Location: Vancouver, BC Posts: 3,289	This is happening because the lamp control module (LCM) is not seeing the required resistance (it is lower now that you have relayed it). There is a way to modify the circuit board inside the LCM (which is located in the relay box under the hood) to "fooling" the auto-check. If I can locate the write-up, I'll post it. __________________ 1997 Audi S6 - Tornado Red on Ecru ---------------------------------- RS2 with MTM Chipset Porsche 928 GTS "big blacks" with 2 piece 993tt rotors S6+ euro sport springs and Boge shocks e-code xenons with range control motors The Rest ------------- 1990 Audi 90q 20V - The Back-up 1991 Alpina B10 BiTurbo - The Hobby Car 1992 VW Passat Wagon Syncro - The Wife's

01-13-2006, 09:29 PM	#6
vtlew Member Account #: 81274 Join Date: Sep 2004 Posts: 356	All I get is a little bullet list when I go to urs4.com am I missing something?

01-13-2006, 09:33 PM	#7
quattro20v AudiWorld Super User Account #: 52091 Join Date: Feb 2003 Location: Vancouver, BC Posts: 3,289	Lobotomizing the Autocheck Lamp Warning Module from urs4.com Phase 3: Lobotomize the autocheck lamp warning module For the auto enthusiast who can't discern that a headlight has burned out, Audi has thoughtfully equipped the car with a warning system that beeps and displays a yellow X-ed out bulb in the autocheck display. The lamp warning module on the UrS4 is a complex piece of kit located in the main relay box in the plenum under the hood. It also warns for burnt out taillights and brake lights, which is a useful feature. The headlight warning circuit consists of two precision resistors and an IC which compares microcurrents across the headlight bulb filaments. Since the ballasts have a different resistance than H1 bulb filaments, the autocheck will drive you to distraction unless you make like a neurosurgeon and lobotomize the thing. The procedure I used is based on Igor Kessel's excellent post in the Headlights section of urs4.com, here. Don your scrubbies, wash up, and let's begin. 1. Remove the lamp warning module and gurney it to the operating table. It looks like a double-wide relay and is located in the main relay box under the hood. 2. Remove the cover from the module. Locate the precision resistors for the headlight comparator (Photo L1). The terminals for the headlights are tagged 56bl, 56bl1, 56br, 56br1. It is easy to locate them by turning over the board and following the foil traces from the resistor joints. 3. Flip the board over and locate the solder joints for the resistors and the terminals connected to the resistors. We are going to short out each resistor by soldering together the terminal joints at the bottom of the board and isolate the resistors from the IC by cutting the foil traces on the board with a scalpel (or reasonable facsimile - I used an Olfa knife). You may want to cut the traces in an area which makes it easy to re-join them in case you want to restore the autocheck operation when you reach your dotage. Photo L2 shows the board with the modifications complete. Make sure the traces are well cut or the autocheck will still activate, usually on bumpy roads. 4. Reassemble the module, insert it in the car, and test. Blessed silence! The operation is a success! The patient is blissfully unaware of the Frankenlamps lurking under the hood! Bwaaahahahahaah!! 5. Enjoy your new high-tech lights __________________ 1997 Audi S6 - Tornado Red on Ecru ---------------------------------- RS2 with MTM Chipset Porsche 928 GTS "big blacks" with 2 piece 993tt rotors S6+ euro sport springs and Boge shocks e-code xenons with range control motors The Rest ------------- 1990 Audi 90q 20V - The Back-up 1991 Alpina B10 BiTurbo - The Hobby Car 1992 VW Passat Wagon Syncro - The Wife's

01-13-2006, 09:35 PM	#8
quattro20v AudiWorld Super User Account #: 52091 Join Date: Feb 2003 Location: Vancouver, BC Posts: 3,289	This has been archived here http://web.archive.org/web/*/http://www.urs4.com __________________ 1997 Audi S6 - Tornado Red on Ecru ---------------------------------- RS2 with MTM Chipset Porsche 928 GTS "big blacks" with 2 piece 993tt rotors S6+ euro sport springs and Boge shocks e-code xenons with range control motors The Rest ------------- 1990 Audi 90q 20V - The Back-up 1991 Alpina B10 BiTurbo - The Hobby Car 1992 VW Passat Wagon Syncro - The Wife's

01-14-2006, 12:58 AM	#9
El Desamparado Junior Member Account #: 81086 Join Date: Sep 2004 Posts: 993	I dont know whats up with that site, yesterday it didnt work for me but today it does. __________________ 95.5 S6 (sold) 86' 4000CSQ (sold)

01-14-2006, 04:33 AM	#10
4Driver4 Tech Guru Account #: 43812 Join Date: Oct 2002 Posts: 27,960	Why do you need the relays? Are the high beams HID too? That's the only reason I can see for adding relays. __________________ 4Driver4 "Never give up the throttle until the bitter end." -RC 1990 Coupe Q 1999 A6 Sedan Q 2.8 2000 A4 Avant Q 2.8 1995 Mazda Miata: the anti-Audi 1999 Mazda Miata: Track beotch 1999 Chevy Suburban: the anti-earth :-( 1990 Nissan Pickup: Snow plow/garbage hauler 1981 VW Scirocco: the car I shouldn't own

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