Bill,
Attached are a couple of photos of the attached rod in my coach. (I'm doing some work on it now so can't fire up to get air pressure to extend the cover). Assuming your '02 is similar to my '01 Contessa, access to the rear air valve is through an access cover under the carpet. The access cover is located in a metal plate that is mounted above the sub-floor in front of the front console. If you have carpet, you should be able to feel the edge of the plate since it is about .24" higher than the sub floor itself.
Some have indicated that you can access the mechanism from underneath, but I haven't tried, as it looks like one would have to strip off the sprayed insulation that covers this area. Hopefully others will comment. Parts-wise, I'd start with BSC or NW RV, once I was sure what needed replacement.
Steve