i have a 2003 Jetta TDI with 83,000 miles. i was driving the other
night and both headlights went out but the high beams still worked and
the dash lights and tails were still on. so i pulled over and checked
the wiring harness to both lights and didn't find them to be loose.
then i hit the hood and the right one came back but i could get the
left one back. 5 minutes later, a cop pulled me over and preceded to
tell what i was already quite aware of. anyway, today i took off the
cover on the back of the left one(the right one is still working) and
check the bulb which seems to be fine. i messed around with the wiring
there for a few minutes to see if the connection was the problem. when
i closed the hood, the left one came back. so...I'm not sure what to
do now. any help would be greatly appreciated

On Apr 16, 1:53 pm, "Dylan" <dylanew... (AT) gmail (DOT) com> wrote:
I find that the halogen cartridge lamps get really sensitive to dirty
connections. Furthermore, if you choose to install Chinese Junque in
place of name-brand cartridges, you will find that the internal
connections fail in fairly short order even if the filament(s) appear
intact. Try a continuity tester on the lamp and/or a VOM on the socket
to determine where the fault may be. Then, search down the relay and
see if that may be faulty, or dirty. The headlights are amongst the
single heaviest draw in the vehicle, taking something on the order of
60 watts (5A @ 12V) each. They are merciless on corroded or dirty
contacts, each one will heat up in turn and fail as the previous
failure is cleaned up. This means relay/switchess, fuses, and
especially plugs.

Clean _everything_ and then check with your meter.

Peter Wieck
Wyncote, PA