Audi A3 8L: Alternator Charging Issue - Indicator Light, Gas Revs, 14.3-14.4V, Bosch 90A

Question

Hello. I have a problem with my alto. When I start the engine, the charge indicator lights up and the alternator is not charging. After adding gas to approx. 1900-2000 thousand. charging is switched on, and the battery is already normal 14.3-14.4v. How can I fix this vulnerability? Bosch 90A...

wojtekcichy · Answer

In audi 8l all alternators were excited with a lamp, so if the lamp is on the board, there is a problem with the regulator. After exceeding certain revolutions, the alternator is excited by residual current. Check the loading under load, if you don't have a clamp ammeter, turn on the main beam and rear window heating, if under load it still charges about 13.5 - 14, then the diodes on the board are OK. Possible replacement of the regulator is very easy, you just need to check the condition of the ring on the rotor. I do not advise you to put Chinese regulators because you will quickly return to the topic. You didn't specify the engine but check what access you have on the back of the alternator because it goes to replace it on the car.

Lechero0 · Answer

AJQ 1.8t engine. Yes, the lamp is on and working. If we assume that the regulator is okay (I will take measurements tomorrow), if someone put a lamp in the board smaller than it should be or led, or can it be the reason? There are 3 wires connected to my alternator. One fat for starter. And a cube with two cables, what are they for? I assume one to excite and the other?

wojtekcichy · Answer

So inserting an LED or a weaker light bulb will also cause no excitation.
1.8t AJQ engine and 90A Bosch alternator, according to the catalog one wire is Lamp the other is the load signal to the computer. So we are only interested in the lamp.
You can take a second bulb, plus to the battery, minus to the L pin (diagram) in the controller and check if it goes off after firing

In case to remove the alternator, remove the washer tank, intake pipe, entire belt tensioner and it will come out elegantly in this direction.

andrzej20001 · Answer

Damaged regulator or freewheel pulley.

wojtekcichy · Answer

The wheel is stiff on this model.

andrzej20001 · Answer

Well, the regulator fell.

Lechero0 · Answer

I checked. After feeding through the resistors +12 from the battery to the excitation, the alternator charges. Now the question is where can I get the +12 signal after the ignition switch? Because as I see it, to get to the charging light in clocks is a lot of fun: /

grala1 · Answer

The lamp in the clocks is a diode and is only for information and not to excite the alternator.
Nobody changed it for you and it would do nothing.
Check the blue wires at the alternator that it is not broken / broken.

wojtekcichy · Answer

If there is only a diode there, there must be some resistor in the clocks and this system will be responsible for excitation of the alternator.
But if the alternator wakes up immediately, check the connections, you have plugs above the starter, there the cable from the alternator connects, check if it is green.

grala1 wrote:
Nobody changed it for you and it would do nothing.

By all means, changing a normal light bulb to a diode would not excite the alternator, so do not tell nonsense that the lamp in the clocks is not from excitation.

andrzej20001 · Answer

As the plug from the altka unplug and the LED in the meter goes out, the regulator went down, the new Bosch about 110 PLN.

Strumien swiadomosci swia · Answer

First of all, the question should be asked what the voltage at terminal L is after switching on the ignition. This determines the rest of the search.

abart64 · Answer

Blue is also brought to the ignition. He gets + in the starter position. Designation 50a as I remember correctly.

grala1 · Answer

It is not from excitation because there is an LED as a indicator. Show me the light bulb in this counter. The toddler times are long over. Excitation does not go from the meter.

wojtekcichy · Answer

The blue +12 cable after the ignition goes to the meter for the lamp, there is a resistor. then the blue cable runs to the alternator. I know this from an autopsy and just have a look at the diagram to find out. The alternator is not computer controlled.
But if you know better how it is controlled then enlighten us ??
In addition, you cut out of my statement a sentence that did not specifically apply to this audi.

abart64 · Answer

A resistor in the meter is probably not needed in this system. It seems to me that at the time of starting alt. gets full power from the ignition switch on L and since it is already turning, it is fully activated after firing. The marking on the ignition block is 50b and not 50a as I wrote earlier.

grala1 · Answer

If you have a diagram, why don't you show it? The cable goes from the ignition to the meter and to the alternator. Power supply from the ignition is only given when turning the starter. If you have a different pattern, show it, unless you have the same one and I can't read the patterns. There is no bulb or resistor to excite the alternator in this meter. I wrote about this car because other cars do not care about this topic. Do you quote me and write about something else? Do you later blame me for correcting you? Did I write something about the computer controlling the alternator here?

Strumien swiadomosci swia · Answer

That is, the voltage is only applied when turning the starter.

wojtekcichy · Answer

Did your friend solve his problem because off top got scary. I enclose the diagram I have and end this without meaningful argument.
I think we presented all the possibilities to a colleague and he can check it out.

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Audi A3 8L: Alternator Charging Issue - Indicator Light, Gas Revs, 14.3-14.4V, Bosch 90A

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