<VV> 65 4 spd back up switch

[The Barneck's]

I am just finishing up the final touches on my daughter's 65 Evening Orchid Monza Convertible and I am having problems with the back up lights.  I installed a new switch and no lights.  I pulled the switch back out and the lights work if I push in on the switch with my thumb.  Is there supposed to be something up in the hole like a spring or a ball bearing or something?  If so, any idea what size?
Doug Barneck
Your tax dollars at work