Vince Megna, the self-proclaimed "Lemon Law King," filed the lawsuit in Dane County Circuit Court. Megna wants the court to order the department to take down a form he alleges is not in compliance with the law and replace it with the correct one.
Megna is also asking that a document that applies to cases brought under the old law be reposted. Until all of that is done, Megna wants Wisconsin to not enforce the new lemon law, which took effect in March.
A spokeswoman for the state Department of Justice, Dana Brueck, declined to comment on the lawsuit.
Wisconsin's lemon law applies to new vehicles on which the manufacturer fails to repair a warranty-covered defect after four tries in one year or fails to provide a timely refund or replacement.
Before the Legislature passed the changes over Megna's objections in December, car owners had six years to sue the carmaker, with mandatory double damages. Now, they have three years and can only get actual damages, or half as much as before.
The law change also required DOT to update and make new forms available that consumers must submit in order to bring a lemon law claim.
Megna was approached by a DOT attorney in April to help interpret the law and draft the forms. But Megna declined, saying it would be a conflict given that he expected to bring cases against car manufacturers and dealers.
One form posted on the DOT website is "replete with errors" and a second required form has yet to be posted, making it impossible for a consumer to bring a valid lawsuit, Megna claims in his filling.
Megna included copies of the emails he exchanged with the DOT attorney to help bolster his argument that the department was having difficulty understanding its duties under the law.
"In my personal opinion, this provision may virtually gut the law," DOT attorney John Sobotik wrote to Megna on April 25 about a form created by the department. "What consumer is going to know he/she has to provide a silly WisDOT form to a manufacturer in order for the Lemon Law to apply to repairs they have done?"
The lemon law changes had broad bipartisan support in the Legislature and the backing of car dealers and manufacturers, including General Motors, trial attorneys and the state chamber of commerce.
Megna has filed more than 3,000 lemon law cases over the past 25 years and won a $618,000 judgment in a 2012 lemon law case against Mercedes-Benz USA LLC.