Can someone grab me a picture of where the Reverse Light Switch is located on the trans and a good way to get to it? My reverse lights havent been working for monthes and inspection is coming up in september so i need to get this taken care of.

Here is a reference to the part Audi B5 A4 Quattro 1.8T > Lighting > Switches > ES#266380 Reverse Light Switch With O-Ring - 012919823F

 

It's pretty accessible from the driver's side wheel well. Take off the wheel and look through the hole. You'll see the plug just above the heat shield on the CV shaft. The actual sensor is on the top of the transmission near the clutch slave. It has a metal finger over it that acts as a retainer.

If you have a digital multimeter, check for continuity through the two pins on the plug (trans in reverse) before trying to replace the switch. It's possible your problem is elsewhere.