OK, I took the armrest off and discovered that the wires were disconnected. The leads from the bell were too short to reconnect so I went to Radio Shack for a new one. I also found that a resistor was hooked into the power line. Not sure why but I suspect it is for the lighted button. The button light wasn't functioning anyway, so I removed the resistor and the bell worked perfectly.
Thanks to all who provided input on this.