Tail lights go on in parked truck?
 

I have a 2005 Dodge Ram 2500 diesel, 4X4, regular cab, manual 6-speed transmission. For the past two nights my tail lights and cargo light have mysteriously turned on by themselves while the truck is parked in 1st gear with the parking brake on. I live in the Colorado mountains, no other homes or vehicles nearby and while the nights have been cold, nothing unusual for this time of year. Is there a short somewhere? Is my truck's computer trying to tell me something? Has anyone else ever experienced this problem?

It's signalling to the aliens. Sounds like the headlight switch is not happy. I haven't looked at a headlight switch in a lot of years. If there is some access, you might be able to spritz the switch with some electronics cleaner.

I've checked the headlight switch and the cargo light wheel switch and they both look fine, no corrosion. I'm wondering if the tail light circuit boards may be the problem, or the trailer plug, but why would the cargo light be affected by either one?

Need to find what is common to both, then get schematics and trace it out. To me, the only thing common to both is the brake switch. But then that would mean that the lights are on bright like you are braking. Is this occurring? Or are the tails on like you just had the parking lights on? How bout the third brake light? Lit up like the brakes are on? You could download service manual from Weedaho signature and started digging in to the wiring and try to trace it out.

Looks to be the lowest tail lamp of the three on both sides, so it's not the brake lamp but the regular tail lamp.

Had that happen to me one time. Turns out it was my trailer brake controller went bad..

Could be. I've got an electronic trailer brake in the truck and now and then it blinks "OC" -- some sort of signal that it's not working -- when no trailer is hooked up when a single red light should be on.

Do you have an alarm system. They can turn lights on. Some of them will turn parking lights and the dome lights on when you unlock it. I don't have one on my truck but the car sort of works like that.

Yea i would look out the window at night and my back lights were on? Found the brake controller to be bad and shorting out. Put in a new one and problem was solved.. No trailer was hooked up when this was happening.