What is this light/button?? 09 F-250 SD 6.4
 

I recently purchased a used 09 F-250 SD, 6.4L. It has this light-on-top/button-underneath -- located under the steering column annd seems to be wired into the dashboard somewhere... but I really can't tell what it is for. Has anyone seen this before? See attachment for photo. Truck doesn't seem to be acting any differently, but it's blinking red and I'd like to know what it could possibly be telling me.