We used to have a Jack in the Box in our neihborhood - a suburb of Philadelphia. I remember it vaguely on the corner of Route 420 and Mac Dade Blvd - I'm guessing it closed down sometime in the late 1970's or early 1980's. I'm pretty sure my parents took me there on a couple of occasions, based on my love for hot dogs, but my recollection of any details fails me.
The place closed down, and there were all kinds of rumors that spread as to its demise ... rumors raning from them using real dogs in their "recipe," (probably not true), to the place being so unsanitary that it had to be closed down (who knows) ... I'm sure the chain just felt it couldn't survive in the Philadelphia area, based on lots of other successful family hot dog restaurants (like The Last Stand).
The chain still seems to be exhibiting some success throughout the country - its website claims that there are more than 2100 Jack in the Boxes operating nationally - mostly out west and to the south. In case you're interested, the closest one to me is in Statesville, NC ... a bit too far of a drive for a wiener.