1989 5.0 c1500 tail light problem

I have a 89 c1500 and have had problems with the passinger tail light working I've replaced the board that the bulbs plug into but after a week or so the bulbs quit working bulbs are good but the board goes bad I'm on my 3rd board and cannot figure out why these boards keep going bad after a week or so checked all connections and they seem o.k any help would be greatly appreciated.


RDH