SUNBURN -- At the Belair and Roth's Mount Vernon Twin.

You keep expecting commercials to pop up in Sunburn," the new Farrah Fawcett movie. It's got all the other prime-time action show staples: sun, skin, chase scenes, exotic locales, bops on the head . . .

But instead of Jack Lord or Mike Connors or some other blown-dry macho her, "Sunburn" has Charles Grodin -- a real live actor. He approaches his role as a bumbling insurance investigator with the same class he brought to "Heaven Can Wait" and "The Heartbreak Kid." And so what might have been a totally mindless movie is instead pleasantly mindless -- just the thing to follow a brain-frying day on the beach.

Grodin's got the role of the funny jerk down to a science. He and his sidekick, Art Carney -- here as charmingly paunchy as ever -- are supposed to be investigating a $5 million insurance fraud case in Acapulco. Grodin's character, Jake Dekker, is a sort of mental 98-pound weakling, an inept guy who's blissfully unaware of his shortcomings. For some reason that's endearing. Fending off a giant lizard ("Hah! Hah!" he yells at it, snapping his bathtowel from 10 feet away), picking a fight with a villain twice his size, inadvertently seducing a tipsy femme fatale -- these scenes, which could have easily ended up producing yawns, are unexpected comic highlights.

As the chic New York model who poses as Grodin's wife, Fawcett ins't as bad as one might expect. She's a little too fluffy to be taken seriously -- a haircut would do wonders -- but shows some flair for comedy, especially when she's supposed to be scared and drops her wide-eyed breathy act.

Despite these pluses, "Sunburn" is still a lightweight, and nobody has bothered too much with the story line. The filmmakers just threw in every action cliche in the book, including driving-the-car-into-the-fruitstand, riding-the-motorcycle-off-the-dock-into-the-ocean and gunfight-in-the-old warehouse. Not exactly the stuff racing pulses are made of.

But if it's a slow night in Ocean City and "Rockford" is on reruns . . .