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
It will depend on if it has HID or Halogen lighting system and also depend on if you need low or high beam. See sources and related links below for 2009 VW Volkswagen Jetta headlight lamp part numbers.
Does it have Daytime running lights? It will be on with them
It's in the D-it-Yoursel section of the Owner's Manual: 1 - Low Beam Left
You change the high/low beam by pulling the signal lever towards you and then again to return.
Pull the turn signal arm toward you.
Bulbs are burnt. replace both. low and high are together in the same bulb.
yes, of course. there are 4 fuses, one each for low beams and one each for high beams. the fuse box is under the dash, inside the cabin, all the way over by the lefthand (driver's side in usa) door. the fuses are in a single row and are numbered, from 1, from left to right. fuse 1 is left low beam, fuse 2 is right low beam, fuse 11 is left high beam, fuse 12 is right high beam.
The 1991 VW Jetta low pressure port can be found on the air conditioning compressor. There are two ports, the low pressure port will be labeled as such.
The 1973 VW Beetle low beam switch can be found on the drivers side floorboard. The low beam switch will be all the way to the left of the drivers side floor.
It means you need to add oil that your oil is low
The starter in the 1989 VW Jetta is located on the passenger?æside of the vehicle inside the engine compartment. It is below the battery box and low on the engine itself.?æ
Low coolant level in the expansion tank.