[Solved] Opel Astra H 2005: Dipped Beam Not Working Post H7 Bulb Replacement - Wiring Query

Hello, I have a problem in my Astra H from 2005. namely the left-hand dipped beam did not work and I changed the bulb but still the light is off. I noticed that the cube in which the bulb is connected was replaced and the cables are connected from it and in the first place I would like to check if the three wires that go to this cube are properly connected. And hence my question how to check it? I would like to add that two cables connect to each other and one is separate. Alternatively, as if someone could advise you on what the problem is because the left lamp operates the parking light and the direction indicator and the low beam does not work.
PS. I bought this car yesterday and the light did not work anymore

Compare the connection to the right lamp. The colors of the wires and even the cube are the same.

piachu1994 wrote:

Compare the connection to the right lamp. The colors of the wires and even the cube are the same.

unfortunately in this lamp all wires are black

profesoor wrote:

piachu1994 wrote:

Compare the connection to the right lamp. The colors of the wires and even the cube are the same.

unfortunately in this lamp all wires are black

I have a stupid question: has it ever worked?

If NO, you need to measure and find the correct order of the wires

If YES, the problem is probably ONLY with ONE cable that has lost contact and probably at the connection point.

As I remember correctly, all non-fueled connections in the car are connected to the mass. If YES, after removing the key from the ignition and turning off the lights on each wire will be mass (short circuit with the body - catch on any unpainted metal element). Multimeter in resistance measurement mode (possibly diode measurement with buzzer), one tip in the car body, the other in each of the cubes contacts. The bush, which has no short to ground, has lost contact ...
Test 2: multimeter in VDC 20V mode, turn on the low beam, one end in the body, the other you fly on the ankle. You should get over 12V on one cable. You turn on the road, you fly ankle again - you catch the road power. This third wire must be the bulb zero. You have it, you know everything. If there is nothing on any of the wires mentioned above, you ONLY diagnose THIS wire. This is success.

a_jablon wrote:

profesoor wrote:

piachu1994 wrote:

Compare the connection to the right lamp. The colors of the wires and even the cube are the same.

unfortunately in this lamp all wires are black

I have a stupid question: has it ever worked?

If NO, you need to measure and find the correct order of the wires

If YES, the problem is probably ONLY with ONE cable that has lost contact and probably at the connection point.

As I remember correctly, all non-fueled connections in the car are connected to the mass. If YES, after removing the key from the ignition and turning off the lights on each wire will be mass (short circuit with the body - catch on any unpainted metal element). Multimeter in resistance measurement mode (possibly diode measurement with buzzer), one tip in the car body, the other in each of the cubes contacts. The bush, which has no short to ground, has lost contact ...
Test 2: multimeter in VDC 20V mode, turn on the low beam, one end in the body, the other you fly on the ankle. You should get over 12V on one cable. You turn on the road, you fly ankle again - you catch the road power. This third wire must be the bulb zero. You have it, you know everything. If there is nothing on any of the wires mentioned above, you ONLY diagnose THIS wire. This is success.

I am not sure if it worked, because when I bought this car, the passing beam was gone. Generally these three wires reach the cube where the bulb from the dipped beam is attached.

the above method will work If you don't catch the measurement on the cube, move the measurement to the place where the cables are connected. That's the only way you can get to it.

BTW: why it works: the lights in the car are controlled by relays, i.e.: the switch in the handlebar and the knob (opel) controls low-signal relay contacts, which transmit 0V to the wires leading to the lamps (mass of the car - in the rest state of the relay) or + VCC (conventionally: 12V, although in reality slightly more).
This fact is used when connecting even daytime running lights (such "non-factory"), where the requirement is to go out when the lights from the set of factory lamps come on. The daily plus is fastened to the plus from the ignition switch (a possible switch along the way), while the minus goes to the plus of the dipped beam bulbs (possibly in position). This "plus" at rest is a light relay strapped to the mass of the car, so we have a closed circuit - LED daytime running lamps work. After switching on the dipped beam, plus and minus daytime running lights is + VCC - no voltage drop - so they don't work.

We want to take advantage of the fact that on one cable on the cube you always have the weight of the car and on two in rest the weight is on and after activating the relay there appears + VCC. Measurement at rest to the car body will reveal LACK OF CONTACT - in other words, a broken circuit. If there is a closed circuit everywhere at rest and the enclosed passing lights are missing + VCC, we will see if the relay hit. As I remember correctly, the dipped / main beam is two-sectioned. And here at 99% we will successfully complete the repair.

You make theories like a space rocket. And the fuses were someone checking? They are separate for the left and right light ...

Show fuses from low beam in Astra h

unfortunately the previous owner mixed up the cables a little but managed to get order and the lights work. Thanks for the help