Headlight switch

My wife has a 97 Caravan 3.3. When you turn on the headlights the switch turns on then, you have to get it iun just the right position to have the headlights stay on. I know the switch must be bad, but how hard is it to replace the unit?
It's gettin dark out and they turn off at the most inconvenient times.

this link may help:
http://www.autozone.com/az/cds/en_us/0900823d/80/1a/45/32/0900823d801a4532/repairInfoPages.htm

Good Luck