1993 Audi 90S 2.8 V6 some questions

[Norton]

Hi, I just bought a 1993 Audi 90S 2.8 V6.

It has some problems, so I'm having some questions.

1. What color is the power steering liquid supposed to be? (Does it have to be green like the G 002 000, cuz the one thats in right now is brownish, seems to work fine)

2. The heater/ac control knobs do not work at all. It seems that there's no cable attached in the back. What cables should I be looking for (what color, jack etc.)

3. I was playing with the fuses (checked them to see it any is blown) and now the central locking doesnt work. When I first bought the car, it wasn't working either, but I managed to find the vacuum leak and fixed it. So until I touched these fuses it worked fine. They are all good though.

P.S. Where is the cable for the central locking pump has to go through? Is it by the driver's side floor?

4. What kind of engine oil should I be using for the 2.8 V6 ? The guy I bought it from was using Super Tech 5W-30.

5. There are two dipsticks on the V6 engine, one of the left and one on the right. Is the left one for the engine oil and the right one for the power steering fluid maybe ?!

6. The RPM gauge doesn't work. What might be the problem? (The car engine revs perfectly, just the rpm gauge doesn't move at all.

I very much appreciate your answers. Thanks.