My client's truck tried to kill him the day he got it. Here's how it went down: he test drove it, negotiated a price and signed some papers. When he took delivery the next day, it was a little colder than it had been the day before. He pulled off the lot and headed down the road. As the engine warmed, he turned on the defroster and hit the fan. A split second later he felt a sharp pain in his eye. He pulled onto a side street and put the truck in park, realizing instantly that something sharp had just come from the defroster duct and poked him in the eye. It was still there. He called 911 on his cellphone and asked for an ambulance. While he waited he called the dealer and told them to come get their truck; he didn't want it anymore. He did not use the magic words but he was "revoking" his "acceptance" of "non-conforming goods".
Everyone has a vague notion defective products can be returned to the seller. But it is not always the case that you can do it so easily, especially with an automobile. The example above is good because it has egregious facts. But first, let's take a quick look at the law. Most of the states in the US have adopted the Uniform Commercial Code which governs the sale of goods. When a buyer accepts goods which turn out to be defective, he may have the right to revoke his acceptance if the goods are defective and the defect is such that it was not apparent at the time of delivery. Most states have adopted the language (below) verbatim. For our purposes, "nonconformity" = "defect".
The buyer may revoke his acceptance of a lot or commercial unit whose nonconformity substantially impairs its value to him if he has accepted it [ ] without discovery of such nonconformity if his acceptance was reasonably induced [ ] by the difficulty of discovery before acceptance.
While this definition looks simple, there is a lot of nuance in there. What sort of nonconformity is necessary for you to revoke? The law says it must be one which substantially impairs the value of the goods to the buyer. What is substantial? We could chase these definitions in circles all day (depends on what your definition of "is" is) but let's get back to my client by the side of the road.
What is the defect in his vehicle? It shoots shards of glass into the eyes of the driver as it is being used for its normal purpose. Did the defect substantially impair the value of the vehicle to him? I dunno. Ever try to drive while you have a shard of glass jabbed into your eyeball? I haven't but my client said it was an issue. I believed him.
I had another client who had the steering wheel fall off in his lap as he was driving along the freeway. Substantial? How about if your car was delivered with no spare tire? I kid you not - the Michigan Supreme Court said, Sure - Why not?!