I've noticed both taillight assemblies on my 2012 seem to collect a little bit of moisture inside the lights, usually little droplets visible in the morning after sitting outside overnight and then later in the day it's more like a bit of a "fog" forms inside the light. The passenger's side seems to do it a bit worse than the driver's side (more condensation visible), but the droplets appear on both of them in the exactly the same areas of the lights - a little bit is visible in the top "clear" turn signal portion and a bit more appears along the innermost edge running along the edge of the trunk lid down to the bumper. The dealer has replaced the passenger's side with a new light housing under warranty, but the new one is still doing exactly the same thing.

Is it possible there's a blocked drain or something somewhere - maybe in the trunk or rear fenders/bumper or something? The trunk always seems completely dry even under the spare, etc. I have noticed on some mornings after a cool night and some rainfall that the rear window has a little bit of fog on the inside at the bottom closest to the rear window shelf, but my previous 06 would do this from time to time as well so I never really thought much of it.

 

The trunk does have to drain water away that runs off the back window. I know the RL trunk hinges are a unique design, and I want to say they may have a drain in the spot they enter the body of the car. It is possible you have a clog somewhere forcing water where it shouldn't be.

Open your trunk and stand in front of it. Have someone poor water or run a hose on the back window and watch the flow.

 

Turns out Acura has a TSB for this issue on the 2010-2012 models, requires a "drain kit" that the dealer has ordered in for me under warranty.

 

Update: there are two TSB's, the first one mentioned it applying to the 2010 RL and listing a drain kit to be installed to remedy it. However a second updated TSB indicates that condensation/fogging "is a normal characteristic" even with the drain kit installed, and it seems in the 2011-2012 models all cars got the drain kit from the factory.

So long story short, if you have a 2010-2012 you can expect to see some moisture/fogging in the taillights, and Acura considers this "normal".

 

I have noticed this on my 2012 RL. It is very, very minor. I noted it when I purchased it CPO in February 2015 when it had been sitting outside on the dealers lot in frigid weather. That was worst I saw, and it was minor enough I did not complain. I drive a lot of miles but my RL lives a very pampered life. I live in a high rise and my RL normally gets parked two levels below street grade in a relatively climate controlled garage.

 

Mine is parked outdoors. The condensation and fogging happens every day here for most of the day, and is always worse on the passenger's side, while on "better" days it isn't as noticeable in the passenger's side light and the driver's side is fine...seems to dissipate as the day goes on but returns every morning. Before the dealer found the TSB's they actually replaced the passenger's side light for me under warranty, and the new one did the exact same thing.

 

Wow! Mine have never been that bad at all. The worst mine have looked is not even as pronounced as the last photo. I wonder if your problem is not the taillamp assembly itself, but a clog in the drain that attaches to the housing?

The next time I have the car parked outside overnight at a hotel I will have to take a look. I am driving to Detroit next weekend where it is usually cool and damp at night this time of year. So I will make it a point to check if the car gets parked outside overnight.

I think we have the same color. Forged Silver Metallic. It really looks great when detailed. I still have clients asking me if I just got a brand new car.

 

The dealer checked all of the drains and they are fine. I expect it's worse with mine because of the climate where I am (atlantic coast of Canada - pretty humid most of the time and cooler temps of course). That's the worst the driver's side ever gets, usually it just barely has a bit of a "fog" visible in the top clear section first thing in the morning, and on some days there is nothing visible at all...while the passenger's side usually will show actual droplets that gradually disappear as the day goes on.

 

Hello BluNosr2, my fellow maritimer.... (I'm in NB), I was getting moisture in my taillights as well last year... Check under your spare tire for water. I found about a 1/2" under mine. After drying this out, the moisture issue seems to have gone away. Not sure where this water came from and haven't had any since. But that would certainly make your trunk area pretty damp and possibly allow moisture in through the air vents on the taillight itself. May not be your issue, but worth a shot.

 

BluNosr2... I appologize... I see in your OP that you checked under the spare already... I read through it too quick. And it was 5am (night shift). LOL. Good luck with the issue. Check the air vents for pluggage on the taillight itself. They are very simple to remove.

 

They always seem to use different names for the colors in Canada. My 2012 is technically called "platinum frost". My previous 06 was "celestial silver"

 

I was in Detroit (Northville) Michigan for the past 3 nights. My 2012 RL was parked outside each night and had heavy dew on it each morning. The taillamp lenses were clear with no condensation issues. My RL was manufactured in March of 2012. I still have to think your condensation issues are from drainage/ventilation issues rather than defective lenses?

 

I have the TSBs from Acura/Honda Canada stating condensation and fogging in the taillights is "normal and does not indicate any problem or defect". The 2010 models didn't use this "drain kit" that was then added to all 2011 and 2012's, so the TSB for the 2010 refers to adding the drain kit (and provides part #'s) , and the updated TSB for the 2011/2012 basically says just to inspect the drains, and no repair or replacement needed if drains are present and clear of obstructions. On my 2012, it seems to have less to do with the moisture or dew the car sees, and more to do with rapid swings in temperature - we had a super heavy fog overnight earlier this week and 95% humidity according to my weather monitor, but the temperature stayed steady - the car and everything else outside was covered in heavy dew in the morning but both lights were clear. Last night, it was a clear evening but went from warm sunshine to near freezing temps overnight, once again high humidity (90%), and this morning both lights had some moisture inside, which was gone by lunchtime.

 

Do you have access to TSBs for this issue? I acquired 2010 Acura RL today and have seen this car 3 times and test drove 2 times and there was no condensation/moisture. Today before I was going to come and pick the car up, dealer washed it and I noticed condensation in the right tail light.

 

I found TSB for this issue and according to that my 2010 RL already has updated taillights with 2 rectangular slits. TSB also talks about some short hoses/tubes to be placed at 45 degree angle, but I don't know if these are installed or not, on my vehicle. It is only the passenger side that is affected. It usually goes away in a day. It was a sunny day and condensation from previous day disappeared, then few hours later, at around 6 in the evening, I noticed some condensation. Go figure.

 

perhaps one could stick a silica packet somewhere inside the taillight where it wouldnt be obvious that there is a silica packet inside the tail light. lol

 

I have seen some condensation in some of my previous cars but that mostly happened when it rained for few days or snowed. It feels as if the taillight doesn't breath that well. On this 2010 RL it can just happen in a dry sunny day. I called Acura dealership and told service lady that my car's passenger side had some condensation in the taillight. I told her about the TSB and she replied by saying that when she scans my VIN, the system doesn't show any "moisture" TSB for my car. I told her the TSB didn't insist on a particular TSB but mentioned 2009-2012 RL models. Since there is no warranty she quoted me almost $160 to diagnose. I better do it myself. My understanding is that there is a long nut that is accessed from the trunk via small opening/cover. Then there is a gutter panel next to the taillight which needs to be removed and that should be it. Does it sound correct?