I have never seen or heard of "lighted decals" but that doesn't mean they don't exist. Suggest you contact the two companies listed-below who manufacture decals of all types to see if they can help you find something:
http://www.vinzdecals.com/index.html
http://www.edecals.com/index.html
Also,
welcome to the forum--great place to otain information and ideas about PT Cruisers. [^]