Should I be worried?

 

just be glad you don't have water coming into your cab from the third brake light. You could get some clear silicone and seal up the light. Might be a pain in the *** once you have to replace a bulb, but it solved my problem.

 

YES, be worried. Leaking third brake lights are common. Check inside your cab at the rear of the headliner for any water. Better yet run an open garden hose on the roof pointed at the light and check for any water dripping inside

 

It is worth checking. My 09 FX4 went in twice for water leaking into cab from that light. Finally, Ford sealed it with silicone while a new redesigned seal (at least they said it was a new design) came in. Had it put in last week. Check it out as it is a very common problem.

 

Yea, I also have condensation in my third brakelight. I get water inside the cab when it rains hard. I'm bringing my truck in for an oil change tomarrow and to check the window, buit I think its the third brake light.

 

We shouldn't have to perform a DIY fix on this. However if you dismantle the case, line it with clear silicone, layer a piece of plastic wrap over it, screw the case back on and let it dry. Once finished drying dismantle again and take the plastic wrap off. You will have created a perfect seal, trim any ugly excess silicone if necessary. I have used this method of repair on leaky windows and doors in both house and auto for many years.
Good luck

 

Take it off and buy a roll of adhesive one side, 1/2" high density foam window seal at Lowe's for 5 bucks. Throw out the completely worthless stock "gasket", re-line with new widow seal and reinstall. Takes 5 minutes and fixed me up 100%. DON'T use silicone on it because you still have to be able to replace bulbs.

This was after I paid a local glass company $115 to reseal my window and it wasn't the problem.

You want something done right......