Light Flickering: Causes and Diagnosis

hello everyone,
Okay, so I went to the 'friendly' *cough* yesterday to have the car checked, because, as previously reported, my lights are flickering (regardless of the engine speed or electrical consumers) and the engine is slightly jerky when accelerating. Well, a proper VW workshop should be able to diagnose that and even consider it a service.
Do you think, no service (--> 43 euros ), and no diagnosis }.
Okay, thanks. Does anyone else have any ideas, or have you encountered this problem before? The error memory is clear, the alternator is also working fine, and it has been tested. All connections are secure, and the mass airflow sensor is also okay.
Thank you for your tips.
Hi Markus,

I had a similar problem with my very old Passat (built in 1986). The regulator on the alternator was defective. Replacing the alternator fixed it.

I cannot say whether that applies to a Golf IV.

best regards
herwig

markus78 wrote:

Well, and what a proper VW workshop is, it can diagnose that kind of thing and even record it as a service. do you think there's no service (--> 43 euros ) and no diagnosis ..

?
So, nothing new: "good" workshops are rare, and insider tips .

My tip: pay attention to the interior lighting.
If it flickers, it's likely due to the alternator, the voltage regulator, or the thick cables leading to the main electrical system.

If not, something will likely start to burn out somewhere in the lighting circuit due to the resistance, unless the heat can be dissipated quickly enough through thick cables or similar.

Hi!

"Has the voltage been checked with an oscilloscope? Or was it only possible to read the error codes for 43 euros? Otherwise... if you can't assess it yourself, I would generally prefer a Bosch service over a VW service when there are suspected problems with the alternator. Of course, this is different in cases covered by the warranty."
If necessary, try connecting a headlight bulb directly to the battery (of course, with appropriate protection!). This will allow you to isolate any potential resistance issues to the area between the alternator and the battery. However, all other electrical consumers should be turned off, as their flickering could create feedback.

Dirk.

P.S.: Are all the mass bands okay and not corroded? If not, please remove and clean them. It's quick and doesn't cost anything.

Assuming you also have a Golf4, there's another ground point located under the battery (not visible from above).
It might be loose or corroded.
You can easily check this yourself, but you will need to remove the battery and its holder.
I don't know for sure if he's actually guilty, but there's a small chance he is - and above all, it won't cost you anything but a little time to check it out.
We once had a similar problem with the brightness of the low beam headlights in a car, and it turned out that this exact grounding point was loose. (However, we also experienced other issues, which are irrelevant to this particular problem).

Martin R wrote:

The Golf4 (let's assume you have one too) also has a ground point located under the battery (not visible from above). Possibly, it is loose or oxidized. . .

Yes, yes, the power cables...

"Whenever I get a car, it's my routine to resolder the crimped connections on all the ground cables in the engine compartment and then reattach them with a dab of grease."

All crimped positive cables receive the same treatment. I find corroded charging and starter cables absolutely disgusting!

On the then-new Golf 3, after just a few weeks, there was already a ring of surface rust forming around a grounding screw located under the battery.

Hmm, didn't we already have a detailed thread about this? I can't seem to find it... that's strange.

Golf4 and flickering lights are as common as Mercedes and the star on the hood...

Solution:

- Point mass (as MartinR correctly suspected).
- Battery depleted (fluid level, charge) -> Capacity measurement at the car dealership, NOT Bosch.
-Billig Lima mit Billig Regler verschlissen (meist der Valeo-Krampf), -> Reglertausch o. Coal swap.
-Main cable and connectors from the alternator to the starter motor to the battery are oxidized (very rare in the Golf 4).

Given the current cold weather, it's likely that your battery is nearing the end of its lifespan. Glow plugs and preheating systems put a strain on the battery, especially since you have features like Climatronic and other extras installed. (If I remember correctly from the GF forum...)

Okay, these are actually some statements . What surprises me is why workshops don't participate in forums more often. Many of these diagnoses are probably random guesses, just like in medicine, and regularly reading these forums could definitely be helpful.

@ulf: Yes, the interior lighting is also flickering quite erratically. I guess I'll have to look into getting a replacement LIMA (alternator). Someone in the GF forum mentioned a kind of goodwill exchange program for the LIMA for around ~80 euros. Does anyone know more about that?

@julian: I don't think it's the battery, because it flickers regardless of the outside temperature.

Could the engine misfire during acceleration (which is particularly noticeable in city traffic) also be related to the LIMACON unit?
Thank you all for the tips!
Greetings and a happy weekend to those who don't have to work .

'I have an Opel Corsa Turbodiesel, and I've experienced the same problem. Driving at night in the dark, with the engine running at 3500 RPM and the headlights and instrument panel flickering rapidly every half-second while on the highway, is quite alarming.'

'In my case, the voltage fluctuated measurably from 12.3 to 13.8 volts... This could be due to a faulty voltage regulator or brushes that are not making proper contact with the armature!'

I had the entire alternator, including the regulator, replaced under warranty (it had only been driven for 5,000 km), and the problem is now gone.

Regards,
André.

markus78 wrote:

Could the engine misfire during acceleration (which is particularly noticeable in city traffic) also be related to the LIMACON unit?

Okay. By "coasting," I understand that to mean completely disengaging the engine, allowing it to roll along at a speed well above idle without any throttle input -> resulting in no fuel injection.

If there's any shaking or vibration, it's likely either coming from the engine mounting system, or possibly from a LiMa (alternator) regulator that's switching in a very uncontrolled manner (purely theoretical ).

Could the engine misfire during acceleration (which is particularly noticeable in city traffic) also be related to the LIMACON (Lima)?
Okay. By 'coasting,' I understand that to mean completely disengaging the engine, allowing it to roll along at a speed well above idle without any throttle input -> resulting in no fuel injection.

If there's any shaking or vibration, it's likely either coming from the engine mounting area, or possibly from a very uncontrolled alternator regulator (purely theoretical ).
I also understand that as a surge. Okay, so there are indeed many reasons to choose the Lima. Oh yes, I completely forgot about that clicking sound that sometimes comes from the fuse box (it sounds like a clicking relay)... does that also point to the Lima? It only happens after starting the engine and only for a short time. (Man, I really want to know ).
thank you

markus78 wrote:

Oh yeah, that clicking sound, which sometimes comes from the fuse box (sounds like a clicking relay), I completely forgot about it... does that also point to the alternator? It only happens after starting the engine and only for a short time.

If the light is flickering, but without making a clicking sound.
(rhyme with me or I'll eat you )
It probably has nothing to do with each other.

It could possibly be the glow plug relay causing the issue, specifically related to afterglow -> it's supposed to cut off above 2500 rpm, if I recall correctly.

Oh yeah, that clicking sound, which sometimes comes from the fuse box (sounds like a clicking relay), I completely forgot about it... does that also point to the alternator? It only happens after starting the engine and only for a short time.
If the light flickers without making a clicking sound.
(rhyme with me or I'll eat you )
It probably has nothing to do with each other.

Could it possibly be the glow plug relay causing the afterglow -> it's interrupted above > 2500 rpm, IIRC.
'Does the clicking disappear above 2500 rpm? I'll try that out. If that's the case, then I'll get a new one. Otherwise...'
8ONobody knows anything about replacement Lima parts for around ~80 euros???

markus78 wrote:

speak, should the clicking disappear above 2500 rpm?

No, after cold starts, there is at least one click after a few minutes when the afterglow function is turned off.

If the engine speed exceeds 2500 rpm (?), it will click more frequently: "Glow" turns OFF, and then turns ON again when the speed drops below 2500 rpm, etc.

speak, should the clicking disappear at over 2500 rpm?
No, after cold starts, there is a clicking sound at least once after a few minutes, when the afterglow function is turned off.

If the 2500 (?) rpm is exceeded, it will click more often: Glow plug OFF, and below 2500 rpm, the glow plug turns ON again }.
Hmm, no, I actually never rev the cold engine above 2000 rpm. So, it seems like the problem is something else.
I'll take care of getting the fuel pump replaced, but thank you very much for the information!
best regards, markus

@ ulf...
Okay, back to the glow plug relay... roughly how much does one of those cost? I'm going to take care of replacing the alternator now, and if that works and it's still clicking, then I'll probably replace the relay. But if it's only a couple of euros, I'll probably just deal with that first.
Thanks, best regards, Markus (who is now completely annoyed).