the entire dash board cluster is powered by two plugs. Depending on what year your car is, the speedometer is either mechanical (91 and older) or electric (92 and up). I know some Hondas have a removable dome over the cluster, but for some, you have to pull the entire dash board. If you have a one-piece dash, tehre's *i think* 6 12mm bolts...

one at the center of the windshield, two at the far edges of the dash where the doors close to meet the dash, two down below those two, and one bolt that's centered below the ashtray, holding the dash to the floor. with those out, you'll be able to slide the dash back far enough to see if any of those plugs have shaken loose.