Quick find on the SIDE of the Museum of Fire Fighting building. Museum is open Sundays 10-2 (May-Oct) but cache is outside and accessible any time.
The cache host, and ones like it, were once used on the back of emergency equipment. When you lift up the red cover to get the cache container, you'll also see the small (deactivated) motor and gears that rotated the light. The cover on this one is red, but it could easily be changed to another color as needed depending on the equipment.
Also close by is an interesting Earthcache (GC773XK).