The cabin air filter or pollen filter is a paper element that filters all incoming air headed for the HVAC system. Usually these should be replaced every 15,000 miles but this simple process is often overlooked. In the B4 (95-97) Passat, this filter is located under the hood in the upper corner on the passenger side under the black plastic cover. Click on the image below to see the arrows.

Start by removing the rubber strip indicated by the blue arrows. It pulls right up and it is only required to remove the passenger side of the strip. Next, the sensor (green arrow) needs to be removed. Simply pull off the entire thing including the mounting bracket. Next, undo the three clips shown with the yellow arrows. Using your hand or a pair of pliers, turn them 1/4 turn and then they will release. You shouldn't have to force them. Then, pull out the whole black plastic cover. This will reveal the filter. It lifts out of the compartment. My filter was pretty much black and had large pieces of dust and leaves and all sort of other debris. It is important that you get a new one and do not attempt to wash the old one. Here is a picture of the new one I got from germanautoparts.com

Before discarding the old filter, remove the two black retaining clips on either side of it. With the foam seal on the filter facing down and the flow arrow on the filter facing down, put the clips on the new filter in the same way that they were on the old filter. Then, put the filter back into the frame on the car so it clicks in. Then, put the black plastic cover back on, clip the circular clips back into the body of the car, clip the sensor back on, and push the rubber strip back into place.

Download a zip file containing a PDF version of this guide and detail images