Speedometer not working, 02,& 05 sportsman

Hi, I’m new, sry about the hijack , didn’t read enough , I’m thinking..
I have an 02 and 05 sportsman both are working in 4wd , I can’t see anything happening with the speedo or odometer, it would be nice to know how fast I’m going, some of the trails have posted speed , and if it’s effecting my 4wd it should be fixed ,
I’m an electronics diagnostic tech but I haven’t had much experience with atv systems , I’m going to be doing tests to find the actual fault, just thought if anyone may have run into this before it would speed up the process
Thank you