I have an old 3 door cooler. The lights have recently gone out and I think the ballasts are the cause. I ordered replacement ballasts from the same company the old ballasts were from. The old Ballasts have one black, one white, and one blue wire. The new Ballasts have the same, but also a red wire. Not sure what to do with the red. The cooler has 2 lights with a switch on each light. There are also starters for each light. Yellow wires go to the switch and the starters, but not to the ballasts. Just wondering if anyone can help me determine where the red wire would hook into. Thank you!

There is a wiring diagram on most ballasts...
Do these new ballasts also have diagrams? If not,
Did they come with any information?

Hello. The wiring diagram shows how to wire the ballast using the black, white, blue and red wires. The problem I ran into is that there is no red wire in the fixtures at all. The lights have black and white wires running from the top of the light fixture to the bottom of the light fixture/switch. The ballast company said the ballasts they sent me were the replacement ballasts for that old model number. I did try hooking the red wire into one of the yellow wires and the light flashed on for a second. I'm stumped. Thanks for your help!

The 3 wire ballast should have a diagram with 3 wires.
Look at the Diagram on the New Ballast and connect as shown.
Don't try to wire the New Ballast with the old Ballasts' wiring.