Here's why much of The Dukes Of Hazzard season 5 revolved around the antics of newcomers Coy and Vance. The Dukes Of Hazzard actually started life as a b-movie called Moonrunners, which was released in 1975. Moonrunners was based on the life of a real moonshiner named Jerry Rushing, and the movie was later retooled to become the more family-friendly Dukes Of Hazzard, which debuted in 1979. The show follows the exploits of Duke boys Bo (John Schneider, Smallville) and Luke (Tom Wopat).
A typical The Dukes Of Hazzard plot revolves around Bo and Luke interrupting the criminal schemes of Boss Hogg, often with the aid of cousin Daisy and Uncle Jesse. Of course, another famous co-star was the General Lee car, which was featured prominently in the show's many chases. Thel show ran for seven seasons, coming to an end in 1985, though the cast later reunited for a couple of TV movies. The show also received a movie version in 2005, which starred Johnny Knoxville, Jessica Simpson, and Seann William Scott (Lethal Weapon). The movie was a moderate success, which led to a straight to DVD, R-rated prequel called The Dukes Of Hazzard: The Beginning.
While TV shows have survived lead actors leaving unexpectedly, the fifth season of The Dukes Of Hazzard was a particularly odd case. John Schneider and Tom Wopat had become increasingly unhappy with the show's quality of writing and became embroiled in a conflict over pay and royalties before filming commenced on season 5. This dispute led to actors Bryon Cherry and Christopher Mayer (Baywatch) being quickly cast as previously unmentioned cousins Coy and Vance Duke, with the original idea being they'd stick around for about ten episodes until the contract dispute was settled.
The Dukes Of Hazzard explained the absence of Bo and Luke by stating they'd left to take part in a NASCAR race. What made the Coy and Vance season so peculiar is that they were pretty much xeroxes of Bo and Luke, right down to looks. The scripts were originally written for Bo and Luke, and there was no real attempt to give them unique character traits or personalities. Presumably, producers worried about deviating too far from the show's formula and felt viewers wouldn't accept characters who strayed too far from the regular Duke boys.
Needless to say, viewers weren't fond of these doppelgangers, who ended up appearing in 19 episodes of The Dukes Of Hazzard season 5. The dispute was finally settled, with Bo and Luke returning from their offscreen NASCAR adventure, and Coy and Vance swiftly departing in the same episode. Much like Chuck on Happy Days - who disappeared following season 2 - Coy and Vance were never mentioned again. The cousins also appeared in animated spinoff The Dukes - before being replaced again once John Schneider and Tom Wopat returned.