Low beam lights will not come on - 2004 Volkswagen Passat

First check light relay fuse, if ok check battery voltage at low beam light terminal, if ok replace low beam bulb, if no voltage check switch side of relay, if voltage replace relay, if no voltage check headlight low beam switch.

check for a damaged wire for the low beam. Also wouldn't hurt to check the ground wire as the high beam will try and ground through the low beam but not visa verse

This is usually caused by a failed front control module as this unit controls the lighting on the vehicle!
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check the light globe as a lot of cars have two filaments in the halogen globe. One for low beam and one high beam filament.
You could get a 12v probe and then pull of the light plug and see if low beam bul is getting 12 volts when lights on low beam.

It can be faulty low beam lamp or its connection issue for low beam lamps.

There are few solved helps links with proper solution to troubleshoot these issues.I suggest you to refer the links below.Click the link:----
Passenger side low beam out?

http://repairhelpcenter.blogspot.com/2012/01/passenger-side-low-beam-out.html

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Low beam HID light goes out? http://schematicsdiagram.blogspot.com/2012/01/low-beam-hid-light-goes-out.html
----------2007 Dodge Caliber: Low Beam Headlight Not working http://technoanswers.blogspot.in/2012/06/2007-dodge-caliber-low-beam-headlight.html
-------------Chevy Tahoe: Low Beam Lamps are not working? http://technoanswers.blogspot.in/2012/04/chevy-tahoe-low-beam-lamps-are-not.html
----------2001 Chevrolet Tahoe: Both Low Beam Lamps Not Working? http://technoanswers.blogspot.in/2012/04/2001-chevrolet-tahoe-both-low-beam.html
--------------2002 Toyota Tacoma: Low Beams not working? http://technoanswers.blogspot.in/2012/04/2002-toyota-tacoma-low-beams-not.html
-----------Low beam headlights Modification? http://schematicsdiagram.blogspot.in/2012/04/low-beam-headlights-modification.html
-----------DRL and Low beams not working? http://schematicsdiagram.blogspot.in/2012/04/drl-and-low-beams-not-working.html
-----------These will help.Thanks.

These trucks are known for bad multifuction switches.
the switch that i talk of is the signal switch , the handle is the switch, it bolts to side of steering column . this switch controls the signals and the headlights and high /low beams. the other thing is the headlight switch connector, the connector some times goes bad and starts to melt or just comes out of the connector. you will need to remove the cover to steering column, the screws are located under the bottom cover in holes. remove cover and check connector and then test for power if you have power going into switch but not coming out then switch is bad.

the last thing is to make sure the bulbs are good , make sure the headlight bulbs are good , and also the driving light bulbs, test for power at the connectors to those lights to.
You will need to do a little testing to find the problem.

the light is out replace it the low side work when u have high beams on ththe short in the light is in the low beam .

low beams are on with the high beams does NOT mean the bulbs are good. The low beams have two separate filaments, one that lights on low beam and one that lights on high beam. That's why the low beams have three terminals but the high beams have only two.It's entirely possible that both low beam filaments have burned out. If the bulbs really are good, then the dimmer switch is the most likely problem.

DID YOU CHECK THE BULBS?

All 4 lights is HIGH beam. The 2 that come on in 'LOW' are the low beams.