Broken Odometer

I have an Audi S4 (year 1993), that i had sitting in my garage for a year and i never really drove it.

Well I decided to dirve it around for fun and its a great car everything even seems to run great for its age. ONE problem is my odometer doesnt seem to work. My speedometer works but the odometer isnt. It says 127,231 miles and even thouhg i drove it all around town it still said that when i got home.

I have heard of this being a fairly easy fix, where i just need to replace a certain fix in my instrument cluster or something. What im asking is if you knowledgeable experts agree that, that is the problem. Also any advice, tips or even a simple explanation on how to fix this would be fantastic!