Thermospa 1988 sierra model.

The light on my hottub will no longer function. I have replaced the bulb, and I have also checked the wire for connectivity. When I press the button on the control panel I can hear a slight click comming from the control box, but no light. I have taken the panel off of the box to check if there were any fuses that were dead, but nothing. Anyone have any ideas as to what might be the problem?
The control box is a balboa model DU-1900D-DCAH if that helps any

The contacts on the bulb socket are probably corroded. Try (with power off of course) scratching the contacts with a paperclip to see it that fixes the light. if that doesn't work use a volt meter to measure power at the socket, then where the light wires connect on the control pack. If you have voltage at the socket, you have another bad bulb. If you have no voltage at the socket, but have voltage at the control box, you either have bad wire or a bad socket. A local spa shop should sell you the wire and socket for $10 or less. If you have no voltage at the box then the relay or transformer has gone bad.