When your car breaks down, how do you know whom to trust? How can you tell if a mechanic is being honest? The news team went to 50 auto repair shops across the Valley in Phoenix to find honest mechanics and the ones who want to take you for a ride. This turned out to be the largest consumer investigation in the market. They used a 2002 Toyota Corolla as a test car and went to all the shops to have it checked to make sure it did not need any repairs. The car had three cameras hidden under the hood and beneath the car to show the engine and other areas that would be inspected. The researcher wore a hidden camera and as she visited big name chains and small independent shops. Shops recommended unnecessary repairs ranging from $30 to $800. After the three-month investigation, some shops corrected their mistakes when confronted, other just would not offer explanations and some did not correct their mistakes.