The size that fits both the wire in the freezer and the male connector on the light. Probably the 18-22.

Thank you. I believe the smaller the gauge number the larger the wire it will support, but, since the connectors are crimp on at the wire end and snap on at the male connector end, a number of gauge sizes seem to "fit". I tried both the 18-22 and the 14-16, and both fit and worked the light. I just don't want to under-size the connector to what the light fixture requires and set up a potential burn out or short situation. Would that suggest going with the lower range number if it both fits and works?

Are you saying that the wire "fits" in the crimp hole in both connectors? Then use the smaller (18-22) one - the hole in the larger one is probably too large for the wire. Use the proper crimp tool.

Yes, it does. I also used a needle nose pliers to crimp the connector. Based on your suggestion, I think I'll start over and use the smaller connector and pick up a proper crimping tool to make a secure connection. Thank you.