# problem: mk4 Jetta no low beams



## Pat @ Pitt Soundworks (Nov 14, 2008)

My friend brought me her car the other day with an interesting problem that I couldn't figure out. Her low beams work intermittently - they'll work until she puts her turn signals on or hits a bump, then she has to flash her high beams to get them to come back on. While her car was in my garage, the low beams refused to turn back on at all. High beams and all other lights work just fine.
- First I checked the elements in the bulbs, still good. 
- I connected power to both the high and low beam terminals, the light shines on both
- I checked power at the harness, 12v on low-beams and 0v on high-beams when "normal", 0v on low-beams and 12v on high-beams when high-beams are turned on. Ground is good.
- I checked continuity between the plug and fuse box, a-okay.
- I checked power at the fuse box, also good.
- According to the Bently, (unless I'm looking at the wrong page 97-259) the power comes in to the switch (stalk), then to the fuse box, then the lights
Now at this point I'm starting to believe maybe the stalk is bad. But the part that really confuses me is that the bulbs HAVE POWER at the harness, yet they don't turn on. But when I manually apply power to the bulb, they turn on. 
Any ideas? Is there a relay that I couldn't find the info for?
edit: found Daytime running lights change-over relay page 97-167


_Modified by Pat @ Pitt Soundworks at 3:23 PM 4-8-2010_


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## Pat @ Pitt Soundworks (Nov 14, 2008)

*Re: problem: mk4 Jetta no low beams (Pat @ Pitt Soundworks)*

OK, had a chance to look at the car again tonight. 
I swapped in a new relay. Now the daytime running lights are on, but as soon as the headlight switch is turned on, the interior lights kick on, but the low-beams turn off. highs still function as normal. Strange part is, when I push the switch in and turn it, the low beams come on with the interior lights. They only work when the switch is pushed and turned (like you're removing it). This function remains with the old relay in as well.


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## jassilamba (Aug 11, 2008)

*Re: problem: mk4 Jetta no low beams (Pat @ Pitt Soundworks)*

Question, are we talking about stock headlights or anything after market. Don't know if it will make sense but sometimes the wires can get shot in aftermarket housings or some other kind of ghost wiring issue.


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## Pat @ Pitt Soundworks (Nov 14, 2008)

*Re: problem: mk4 Jetta no low beams (jassilamba)*

Everything about the car is stock.


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## dennisgli (May 17, 2003)

*Re: problem: mk4 Jetta no low beams (Pat @ Pitt Soundworks)*

Sounds like a bad light switch.


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## Pat @ Pitt Soundworks (Nov 14, 2008)

*FV-QR*

replacing the switch was the first thin I tried


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## dennisgli (May 17, 2003)

*Re: FV-QR (Pat @ Pitt Soundworks)*

Then I'd check the high/low beam dimmer switch.


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## Pat @ Pitt Soundworks (Nov 14, 2008)

*FV-QR*

Do you mean the one in the column or the relay? Certainly not the dimmer switch by the headlight switch...


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## john_tsouris (Feb 21, 2010)

The problem is in the high beam switch assembly which also houses your turn signals and possibly cruise control. There are some electrical contacts in the assembly which dis-connect the low beams when you put the high beams on. Constant use of the high beam switch will create arcing on the low beam switch which makes the contacts not conduct electricity anymore.

The repair is to either replace the assembly, $300 at dealer, $100 or less do it yourself, or take the assembly apart and clean it for free. (2 hours or less)

Instructions on taking your steering wheel off here: http://forums.tdiclub.com/showthread.php?t=151557

Instructions for fixing the switch here: http://forums.tdiclub.com/showthread.php?t=167831&page=4

P.S. If you own a VW, especially around model years 1999 to 2004, there is a rare but devastating problem with engine coolant being literally pumped through all electrical parts of your car.... destroying it. Repair cost = $8,000. It is called coolant migration. Check your VW right now (takes two seconds, literally), and do a two-minute procedure to fix your car to prevent the problem here: http://www.myturbodiesel.com/1000q/multi/coolant_migration.htm


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