Is there a way, and if there is, what is the best way to keep moisture out of my taillight? Thanks

 

If there is moisture in your taillights, your seal is broken somewhere. About the only way to fix them is to remove each one and dry them out using air, then find the source of the leak and seal with clear silicone.

Its a lot cheaper than buying new ones.

 

yes, your assembly is glued together in two pieces. take them out of a nice sunny dry day and let them sit in the sun for a few hours. then get some clear silicone from the hardware store(home depot, lowes) it is cheap. then run some along the connection between the red lens and the plastic housing. somewhere the sealant has come loose and allowed water in