Those are the typical symptoms of problems with the multifunction switch. After frequent use the grease inside becomes impregnated with metal particles due to wear on the contacts. The correction is to repair (clean) or replace the switch. There's a good walkthrough here, the reference vehicle is a 97, you may notice a couple differences, however the process is basically the same:
http://www.automotiveforums.com/vbul...d.php?t=577320