i am working on a drag racing grooms cake. The "Pre-Stage" "Stage" sign will go on a sheet cake. is there a good/non difficult way to make the yellow, red and greens lights light up?

wish I could help you!!  

Not sure the size you will be making, but I bought some small battery operated LED's from Amazon to light up a Captain America/Iron Man logo on a cake. You just twist and they light up. Mine were clear, not sure if they come in colors. The box said they would last 8 hours, but my friend said her fridge was glowing through the next day :).