How JustAnswer Works:

  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.

Ask Josh Roberson Your Own Question

Josh Roberson
Josh Roberson, ASE Certified Technician
Category: Audi
Satisfied Customers: 72
Experience:  1 year Audi experience, ASE Master Technician, Audi factory trained
1286960
Type Your Audi Question Here...
Josh Roberson is online now
A new question is answered every 9 seconds

2004 Audi A4. With the ignition on, my headlights turns

Customer Question

2004 Audi A4.

With the ignition on, my headlights turns on. Lights are on no matter if the Headlight switch is off, auto or on.
Submitted: 5 years ago.
Category: Audi
Expert:  Josh Roberson replied 5 years ago.

I believe I may be able to help you. Before we get into a wiring problem (which can get complicated) let's rule out a bad switch. Try disconnecting the headlamp switch. Turn the switch to the "off" position and then push it in. With the switch pushed in, turn it clockwise until it stops, it should stop around the "auto" position. Once it stops, pull switch out. Once the switch is out you can disconnect the connector. If the lights go out with the switch disconnected you probably have a bad switch. If they remain on, you more than likely have a wiring problem.

Customer: replied 5 years ago.
Hello Josh,

Based on your input, I believe I have a wiring problem. The headlights are still on with the headlight switch disconnected from the connector.

What do you advise?
Expert:  Josh Roberson replied 5 years ago.
My information system will not give me wireing diagrams without inputting a VIN. If you can get the the VIN I can better assist you.
Customer: replied 5 years ago.
waulc68e64a217668

audi A4 quattro 2004

Someone mentioned to me that headlights might be always on because somehow the VAG is on Canadian mode. Not sure about this however.

Thanks,
Myron
Expert:  Josh Roberson replied 5 years ago.

Wrong coding is a possibility, but theoretically the coding will not change by itself. So, as long as nobody as gone into the system and changed anything that shouldn't be the issue. Now that I have the VIN I can get more specific information on everything including the wiring diagrams. According to the information I have, your car has the HID gas discharge headlamp system. This changes things a little bit.

I believe the switch may actually be your problem, and here's why; when the headlamps turn on and stay on it typically means they have gone into a "default mode". Default mode is a safety feature that will automatically turn the headlights on if a fault is detected within the system. If there is a fault in the switch, the control module will turn the headlamps on to prevent you from having to drive around at night with no headlights. If you unplug the headlamp switch, the control module detects that as an open circuit fault and the control module will turn the headlamps on. At this point I would recommend replacing the switch. If the switch does not solve the problem I may need fault codes form the headlamp control module. Any repair facility with a VAS tester, VAG COM, or Ross Tech software should be able to retrieve any faults from the system.

Customer: replied 5 years ago.
Thanks. The switch is very expensive. Is there a place I can get the switch (with auto sensor) at a more resonable pricing. I tried ebay and they only have non-auto.

If it turns out to be the switch, I will send you your fee.
I have a obd2 auto scanner, but I think the interface is not standard. What is the type of plug it needs if the autoscanner would work at all?

Best regards,

Myron
Expert:  Josh Roberson replied 5 years ago.

From 1996 onward all OBD2 connectors are the same. On the other hand, the programming can differ. With most typical scanner you can only get engine codes or "P" codes. To scan all other control modules in an Audi you need special progams. VAS testers are the testers provided by VW and Audi, VAG COM and Ross Tech and independant programs that will communicate with control modules apart from the engine and transmission module. VAG COM is more widely used than Ross Tech, but it's rather expensive. I've used VAG COM before, but not Ross Tech. The VAG COM software will do most of the things that can be done with the VAS testers. However, there are still some things that can only be done through a VAS tester, but for what you need VAG COM should work fine.

As far as a cheaper aftermarket part goes, I wouldn't recommend it. There are some manufacturers that I wouldn't recommend putting aftermarket parts on, and Audi is one of them. Aftermarket parts don't always use the same specifications that the manufacturer does, therefore they don't always function just right or they don't fit into place as well as the original equipment does.

JustAnswer in the News:

 
 
 
Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.
 
 
 

What Customers are Saying:

 
 
 
  • I would (and have) recommend your site to others I was quite satisfied with the quality of the information received, the professional with whom I interacted, and the quick response time. Thanks, and be sure that I'll be back whenever I need a question answered in a hurry. Stephanie P Elm City, NC
< Last | Next >
  • I would (and have) recommend your site to others I was quite satisfied with the quality of the information received, the professional with whom I interacted, and the quick response time. Thanks, and be sure that I'll be back whenever I need a question answered in a hurry. Stephanie P Elm City, NC
  • used your service this weekend with "Trecers" help. thank you ,thank you, thank you. replaced an A/C fan motor. Local Auto Zone had part. $15.00 "tracer" fee and $40.00 for parts, I saved several hundreds of dollers at a shop. i will recommend you and use you in the future. David L. Richmond, TX
  • 9 dollars, 2 hours of my time, and I drove away. Your diagnosis was right on the mark. Thank you so much. Phil Marysville, CA
  • Lurch. Thank you very much. I had real doubts about this website but your promptness of response, quick followup and to the point answer with picture was incredible. Charles Walnut Creek, CA
  • As a single woman, I really appreciate an excellent and affordable opinion.
    Thank you Geordie, I will not hesitate to contact justanswer in the future!
    Sue Charleston, WV
  • Another great insight to what may be the problem. I will have my mechanic take a look at it tomorrow. Thanks again, Frank...you do indeed know your stuff. Jim Castleberry, FL
  • Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help. Mary C. Freshfield, Liverpool, UK
 
 
 

Meet The Experts:

 
 
 
  • AudiDoc

    Independent Audi Shop Owner

    Satisfied Customers:

    1681
    I've been working on Audis since I was 18 and own an independent Audi repair and performance shop
< Last | Next >
  • http://ww2.justanswer.com/uploads/audidoc/2008-12-23_175252_headshot.jpg AudiDoc's Avatar

    AudiDoc

    Independent Audi Shop Owner

    Satisfied Customers:

    1681
    I've been working on Audis since I was 18 and own an independent Audi repair and performance shop
  • http://ww2.justanswer.com/uploads/35/350matt/2012-6-7_182356_matsavatr.64x64.jpg Matt's Avatar

    Matt

    Engineer

    Satisfied Customers:

    461
    Mechanical Engineer with 20 years experience in the auto industry, 8 yrs in formula 1 engine testing
  • http://ww2.justanswer.com/uploads/MI/mikeamechanic/2013-4-2_175558_photo.64x64.JPG Mike Kelly's Avatar

    Mike Kelly

    Audi Mechanic

    Satisfied Customers:

    259
    17 years experience as a auto mechanic, foreign and domestic.5 years running my own repair business.
  • http://ww2.justanswer.com/uploads/FourRingsTech/2010-01-26_135603_GetAttachment.jpg Michael Miller's Avatar

    Michael Miller

    ASE Certified Technician

    Satisfied Customers:

    241
    ASE Master Technician. Audi certified, including R8 and TDI (clean diesel).
  • http://ww2.justanswer.com/uploads/NA/nabilc/2011-1-24_205715_jap500.64x64.jpg Billy's Avatar

    Billy

    Trainer/Master tech.

    Satisfied Customers:

    229
    Trainer 8+ years, Master tech. 10+ years, SAE member
  • http://ww2.justanswer.com/uploads/tsmodie/2009-6-10_144056_tim.jpg Tim Mohr's Avatar

    Tim Mohr

    ASE MASTER TECH

    Satisfied Customers:

    204
    30 YRS EXPERIENCE, FOREIGN AND DOMESTIC, GAS AND DEISEL
  • http://ww2.justanswer.com/uploads/CA/caprio23/2011-12-13_155550_20111213105344.64x64.jpg Anthony's Avatar

    Anthony

    ASE Certified Technician

    Satisfied Customers:

    174
    ASE Master Automobile Technician with over 20 years exp. in this field.
 
 
 
Chat Now With An Audi Mechanic
Josh Roberson
Josh Roberson
64 Satisfied Customers
1 year Audi experience, ASE Master Technician, Audi factory trained