It will be at the palazzo parking lot during MFEST friday sat and sun. The guy who runs it is "FASTDAD" he does a great job. You will see him when you pull in friday in the garage. Just sign up. i believe its 40$ for exterior/interior wash though.
As far as tomorrow I hadn't heard of anything. In the past there never was a car wash so unless this is something completely new then there wont be this year either. PM Laidback the owner of MFEST name is Chris maybe he can help you out. SEE you in 2 days!