When I first bought my 65 Ford F250, there was a light that lite up my speedometer but now it doesn't lite up at all, is there just a small light bulb behind there? I cant find one. also, a spring fell out that was around the light switch, is that why it stopped working? thanks

 

That spring is the resistor that controls the current to the dash lights, to dim or to brighten them. If it fell out, there is no power getting to the dash light bulbs.
The entire light switch will need to be replaced.

 

Well thank you very much!