I took off my flooding headlamp assemblies to drain them and seal them. It was interesting to see a blue dot sticker cover over a 1/16" drain hole in the lower outer corner. I peeled the dot off to drain the housing. Then I noticed a corresponding hole in the mounting bracket.
Is something missing, like a vent tube? Should I leave the dot off so it can breathe? Maybe GM planned to use the hole then didn't? Don't most cars have a vent tube?


drain hole in housing

corresponding hole in bracket

 

They are intended not to vent and always stay dry. They should unless the last guy that put a lightbulb in did not do it correctly. The rubber seal is just that, a seal. Some replacement light bulbs have a seal pre-installed and will not allow the bulb to properly seat to the bucket assembly (two seals is too thick). Other times, if you pull out a dead bulb, the seal may come off with it and if the new bulb has no seal, or you do not put the original seal back= leaks/fog/fluid. I also think that since these trucks are now getting old, the seals could shrink and allow moisture intrusion as well.

That blue dot sticker is to allow drain and change of the headlight fluid along with blinker fluid for regular maintenance.

 

The local auto parts store were out of stock for headlight fluid and blinker fluid!