2000 Ford F-250 Electrical Malfunctions

The other day when I got in my truck to leave work, the heater motor was running with the ignition off. The next morning when I left for work, the air bag warning light came on and the heater motor still will not shut off with the ignition key. And now, the third day my cruise control stopped working and my speedometer is jumping around.

Last winter my heater motor was doing the same thing as described above but this time when I tried to set the cruise the horn would honk. About 2 hours later when the truck was parked the horn started to blare and the only way I could get it to stop was to disconnect the batteries. After a couple of days I re-hooked the batteries and everything was fine until now.