3 Problems - Tacho, blower and light

Hello V8ler,

I have an Audi V8, 4.2L BJ 1992 with approx. 200000km. I'm very happy with my car, although I've already had some delicate repairs that went from the simple window lifter, to the old brake problem, to the cylinder head seal. But after I want to drive the car even longer (it also serves me as a brilliant towing vehicle for the trailer operation) I ask if you possibly. have some answers to my problems/questions...

Problem one: I've been having problems with my tachometer for some time. The problem is that with a floor shaft, or a curb of the speedometer completely fails. Easily knock on the tachometer, either on the disc, or on the amature board sets the tacho back in motion for a while. To take it away from the front, I've been looking for it in the forum - the on-board computer, the odometer, cruise control and also the "climate-system-board computer on channel 17" are out at the same time. There's nothing going on. Okay, so I tried to get the whole module from below, but there was nothing going on. Now my questions: does it do me any good if I expand the whole amaturary board? If I then get to the "tacho module" and can I do anything at all? (cold soldering points?) What do I have to take into account (I have a little bammel because of the airbags) As far as I have seen this, I have to degrade all the root wood parts first and then come to the screws of the amature board - is that right? Can I possibly get an explosion picture of the whole thing? Is this a known problem of the V8s (as well as of the Ufo brakes :-(( ) ?? Would be nice if someone could give me a hint.

==References== Problem is my blower: after a certain time, the blower starts to whistle uncannyly. When I turn off the blower and then go back to automatic it can be that the whistle is gone - but not either. Sometimes it doesn't go away for a very long time. What's funny is when I'm alone, the problem has occurred very rarely. The car is a car that is used either by a car, or by a car. Trailer heavy loaded. What's still interesting is that it mainly starts when I'm in a sharp curve??? I suspect that it's the fan wheel from the fan that's kind of slipping through, or. Somehow just starting to quibble and whistling. Now, my questions: Does anyone know the problem? Is there a solution? How can I get to the fan wheel without all the ventilation flaps falling down? There may also be. An explosion drawing that could help me here?

And now to my three. and for the time being the last problem: My headlight glasses are quite cloudy from the inside. Is there any way that you can expand and clean the glasses individually? I tried to clean the glasses through the lamp openings, but somehow I didn't have such a real success. My question: can you remove the glasses individually for cleaning, or do I have to remove the whole headlight? What do I have to consider?

So, I hope someone can help me...
Many greetings
Klaus