An alert has been issued for car buyers, Local 4's Ruth Spencer reported. A consumer advocacy group claims customers are being taken for a ride by deceptive sales tactics.

CAR SALES TACTICS To see the scam alert issued by Public Citizen, click here

The organization Public Citizen is calling on law enforcement to investigate what it calls widespread fraud in the auto sales business.

The group claims even customers who do their homework are unwittingly being taken for hundreds, or even thousands, of dollars.

"While many consumers suspect that auto dealers are not always paragons of virtue, most have no idea how vulnerable they are," said Joan Claybrook, president of Public Citizen.

Duane Overholt says he's well aware of the problem, Local 4 reported.

Overholt worked in auto sales for 20 years until he blew the whistle on his car dealership.

By then, he estimates he had ripped off consumers for about $33 million.

"When you're working in the auto sales business, you get the feeling that you are invincible," Overholt said. "You think you can do anything and get away with it."

Local 4 learned that some common scams include adding fees for equipment that should be standard, or charging for extras the customer never requested.

Public Citizen claims some dealers also take kickbacks from banks that charge car buyers higher interest rates.

The National Automotive Dealer Association says it condemns fraudulent or deceptive behavior.

Experts say car buyers should take note of the following tips when shopping for a car:

Get your loan from a bank that's independent from the dealership
Never sign blank forms
Don't agree to an arbitration clause -- that limits your options down the line
Watch out for extras
Sign all of the paperwork before you drive the car home