Help I have an 06 TL.. It seems like the tail lights have a mind of there own..Both come on and off as they please. It seems to do it more when its raining out.. I have checked every I can think of and cant find any form of water/moisture any where.. To my knowledge the windshield or sun roof has never been replaced.I have checked everything I know to check including the battery and cant seem to figure it out.
ANY IDEA'S??????

 

your tail lights stay on? like lit up? what about when the car is off?

check the LED boards themselves on the actual taillights. make sure the gaskets are still in good shape and no water is getting in there. you'll need to physically remove the tails to do this.

 

maybe brake pedal switch under neath brake pedal

 

yes the lights stay on after the car is off..not the brake lights but the tail lights.. No other lights are on. I have unplugged the brake switch and the battery and nothing. They are still on.. I unplugged the tail lights so the battery wouldn't drain last night.

 

I also noticed that when I unplugged the brake switch and pluged it back in my 3rd brake light now stayed on..but I didn't notice it on prior to removing the switch

 

sounds like you have a leprechaun in your trunk.

 

You probably moved it a little when you unplugged and plugged it in. Push it toward the brake pedal until the light goes off.

I was going to recommend what Justin said until you said it was the tail lights and not brake lights. Does anyone know if the parking lights are a traditional switch to relay to lights or does the switch tell the ECU to turn on the light and the ECU triggers a relay?

Is it just the tail lights or all parking lights?

The more I think about it, the alarm will flash the parking lights so obviously they can be turned on independently of the switch on the stalk. If it does it worse in the rain, I would be looking at the ECU, make sure it's not getting wet, which is assuming the anti-theft is built into the ECU.

Has the windshield ever been replaced?

 

Just the tail lights. I pulled back the carpet last night and from what i could tell it was completely dry. To my knowledge the windshield has never been replaced. I've only had the car a year.. The trunk completely dry and I even felt around the sun roof.
Today I plugged the taillights back in and they have stayed off ...so finding the problem now is gonna be even harder till they act up again

 

Did I read this correctly, you unplugged the battery and the lights remain on?

 

No sorry the obviously went off when the batteryas disconnected.. Left the battery undone for 30 mins but when I hooked it back up they were still on