[Solved] Audi A4 B6 2002, 1.9 TDI, 130km - Left Dipped Headlight Issue: Bulbs Burning Out & Diagnosis

Hello, I have a problem with the left headlight (low beam) in AUDI A4 B6 2002. 1.9 TDI 130 km, namely after replacing a burnt bulb, the headlight stopped working on the same day (after about 10 minutes of driving after replacement). I bought a new bulb and it didn't work from the start (it burned out right away). I would like to add that I checked the bulbs and both were operational before connecting them to the car, but after trying to turn on the lights, they burned out (but there is no sign of burnout). I measured the voltage on the wires supplying the voltage to the bulb and it was over 12 V. To sum up - the voltage is there, but the bulbs burn out, so I suspect a short circuit, but I have no idea where to look for it. I would like to add that there are no dipped beam fuses and the right headlight is working all the time. Please help.
Edit: May 19, 2018 22:03 I forgot to add that I checked the car's computer with the torque + ELM 327 application and it showed no errors.

netvlc wrote:

namely after replacing a burnt bulb

This I understand the usual H4 or H7?

netvlc wrote:

I measured the voltage on the wires supplying the voltage to the bulb and it was over 12 volts

How much exactly and in what state of engine operation?

netvlc wrote:

In conclusion - the voltage is there, but the bulbs burn out,

So either the voltage is too high or the bulbs you assume are some crap.

netvlc wrote:

therefore I suspect a short circuit, but I have no idea where to look for it.

Why a short circuit? If the voltage is too high, first of all, a suspicious voltage regulator that has already killed the battery. Other possible causes are loose battery clamps, with the battery disconnected, the alternator voltage regulator has the right to "freak out" ...

netvlc wrote:

but after trying to turn on the lights, they burned out (but you can't see any sign of burnout)

Checked with an ohmmeter - have a break?

The bulbs are H7, the voltage on the wires was 12.3 V after turning the key in the ignition switch, the burned bulbs were checked with a multimeter - there is a break and by connecting the 12 V power supply to them from the screwdriver battery (the bulbs did not light up). The battery terminals are not loose.

netvlc wrote:

Bulbs are H7

No-name or some "normal" company?

netvlc wrote:

the voltage on the wires was 12.3 V after turning the key in the ignition switch,

12.3V with the engine running is not enough (but too low voltage does not make the life of the bulbs shorter). If the measurement was with the engine not running, the engine must be started and the measurement repeated.

"Normal" bulbs, additionally checked earlier in another car and they were ok. Measurement made with the engine not running.

Check carefully the cube / plug of the bulb if it is not overheated (if so, change to ceramic).
In addition, to check the cables for a short circuit, whether any of them are not frayed, or if necessary. with cracked insulation.

Hello again, so far the problem has been solved. I cleaned the cube thoroughly, which was attached to the bulb, and did not push it too hard. I'm not sure what caused the breakdown of the previous bulbs, but it turns out that it was related to this cube. Thanks to everyone for your help.